Ensemble Darkhorse/Western Animation

These series have so many darkhorses that they spawned their own subpages:
 * My Little Pony: Friendship Is Magic
 * Transformers

"My cabbages!"
 * Looney Tunes has a fairly big history of this. Their first big star after Buddy and Beans The Cat was a minor character in a series of shorts about a group of grade school animals, but his role as the stuttering, somewhat unlucky Straight Man role proved popular with fans and Porky Pig soon became their premiere character. After a few years, a cartoon featured Porky going on a ducking hunting trip, running into all sorts of wacky mishaps, one of which was an off kilter duck that only appeared in two scenes (and the credits), put his loony, unconventional antics proved so popular that soon that "Daffy" Duck got his own cartoons and became their next star, until the process repeated itself yet again with their now premiere character, Bugs Bunny.
 * One of the strangest examples: the nameless drunk cat with the red nose, big lips, saggy jowls, dickie shirt with bow tie and bandage on his tail. He only appeared in the Bob Clampett-directed "Kitty Kornered" as a pet of Porky Pig who teamed up with Sylvester and two smaller cats, but he proved popular enough to appear in many of the spin off series of the 1980's and 90's including Tiny Toon Adventures and The Sylvester and Tweety Mysteries.
 * Marvin the Martian also fits this only having a handful of short in the Looney Toons canon but ended up becoming the primary antagonist in Duck Dodgers and even getting his own music video
 * Another example would be Taz the Tasmanian Devil. Originally he was only going to appear in one cartoon but he was saved by fans requesting he make more appearances; he made 4 additional cartoons and a major role as a villain in the Christmas special, proving popular enough to get his own TV show. He is now part of the main character rosters and one of the most recognizable characters in the series.
 * To a far lesser extent, Penelope Pussycat, originally the unlucky nameless cat who would get chased by Pepe in his shorts has been gaining her fair share of popularity these days as well.
 * Also Pepe himself, although to certain other people he is seen as The Scrappy.
 * There's also Michigan J. Frog. He appeared in just one seven-minute short, but is one of the more popular and recognizable minor characters in the Looney Tunes universe.
 * A certain certified genius coyote comes to mind...
 * Speaking of Taz-Mania, it had a few as well, including The Platypus Brothers, Bull Gator and Axel, Hugh and Digeri Dingo.
 * Numerous characters in Family Guy. Includes Herbert the pedophile, Ernie the Giant Chicken, Greased-Up Deaf Guy, Ollie Williams, Bruce (and the random animals that share his voice), and the evil monkey in Chris' closet.
 * Several characters in Justice League Unlimited, but most notably The Question. How could you not love a character that breaks into secret government organizations while singing off-key Britney Spears knock-off tunes by boy bands which he claims tie in with the Illuminati?/
 * He struck a chord with more than the audience. After his debut in "Fearful Symmetry", the writers themselves were sorely tempted to drop everything and make The Question Show.
 * The fact that he was voiced by the same actor who played the enigmatic Weyoun on Star Trek: Deep Space Nine didn't hurt, either.
 * The Flash was the Ensemble Darkhorse of the original series. In fact, his lack of presence in the first season of Justice League Unlimited was one of the main reasons fans bashed it.
 * Depending on who you're talking to, Hawkgirl is either an Ensemble Darkhorse or a Creator's Pet.
 * Lack of Flash is so noticeable that it was identified as the reason why the alternate universe Justice League turned into the tyrannical Justice Lords.
 * Subverted with Captain Atom, who appeared in the first episode along with other soon-to-be-popular characters, but never managed to achieve popularity. Still, he was able to fight Superman one-on-one and almost thrash the big man, in spite of being a supporting character.
 * Chernabog and his sequence, Night on Bald Mountain, from Fantasia. Everyone remembers the beautiful pieces of music from the whole thing, but this was the one that stuck to everyone's memory. Pretty much everyone that ever watched this was in fear and awe of Chernabog, the sequence is regarded as a Crowning Moment of Awesome and as Nightmare Fuel that caused the Slavic Satan to haunt many's memories to this day, and it should come as no surprise that, of all the things from Fantasia to put into Kingdom Hearts, they chose Chernabog.
 * Pinky and The Brain from Animaniacs, which led to a Spin-Off starring them.
 * Slappy Squirrel.
 * Minerva Mink.
 * Robotnik from Adventures of Sonic the Hedgehog is arguably a more popular character than Sonic himself, thanks to Youtube Poop and Long John Baldry's show-stealing performance.
 * A classic example: Donald Duck arguably fits the bill (if you'll mind the pun). After Mickey Mouse became much more relaxed and "boring" (an attempt to make him a better role model for the kids who liked him) a character was needed to embody the more negative qualities that made the cartoons fun. Donald's bad temper and amusing speech patterns made him a hit and he is usually at the center of most of the big laughs in the cartoons he is featured (or, as his popularity has grown, starring) in.
 * Scrooge McDuck started as a supporting character in Donald's comics, but eventually became popular enough to be spun off into his own series. Scrooge is much more popular than Donald in Finland and France, where the magazine devoted to Carl Bark's universe is called "Picsou Magazine". (Picsou being the French name for Scrooge). Oh, and let's not forget DuckTales, which puts Donald on a boat in the first episode, reducing a character that was always going along with Scrooge on his adventures to a guest character.
 * Considering Scrooge started as nothing more than a caricature of thrift in a propaganda cartoon during World War II, thats one heck of an escalation.
 * He didn't. He started out as a Dickensian miser in a christmas story in 1947. However, most of Donald's relatives and other Disney characters fit this trope. His nephews: started in a Sunday page in 1937 and a cartoon in 1938. Both end with them leaving their uncle. Goofy: started out as a theatre-goer with a goofy laugh called Dippy Dawg in 1932. Gladstone Gander: Donald's (not yet lucky) cousin coming in winter 1947/1948. Gyro Gearloose: started his career with a half-page cameo in a story. And so the list goes on.
 * Panchito Pistoles and José Carioca, Donald's fellow Caballeros, are well-liked among the fanbase as well, to the point that they had a guest appearance on Disney's House of Mouse as well as their own ride (Gran Fiesta Tour Starring The Three Caballeros) in the Mexico Pavilion of Epcot's World Showcase (which was renovated from its former status as El Rio del Tiempo)? Ditto for the Aracuan Bird, who was popular enough to torment Donald in future shorts.
 * Woody Woodpecker originally debuted as the villain of the Andy Panda cartoon short Knock Knock in an attempt to deliberately invoke this trope-Walter Lantz and his cartoon studio were hitting hard times after the series Oswald the Lucky Rabbit ran out of gas, and Andy Panda wasn't the new hit star they needed badly to rejuvenate the ailing studio. Unsurprisingly, Woody became an instant hit upon debut and went on to immediately star in his own smash hit series of short subjects.
 * Despite appearing in only five episodes, Cheese from Foster's Home for Imaginary Friends is one of the most well-liked characters, dominating most of the merchandise of the show. This is likely because the target audience is young, and Cheese is The Ditz. Cheese does mostly what was the most fun/wacky when we were five years old... unlike Ralph who only display pure idiocy but not high-octane playfulness. Which is why Cheese is the ensemble darkhorse.
 * Invader Zim has Tak. Despite appearing in one two-part episode and having a vocal cameo in another, the amount of Fan Art depicting her can easily confuse new fans into thinking she's part of the main cast. She had one planned reappearance before the cancellation of the series, but it's certain her popularity would have resulted in many more. Given that she was the first competent Irken we had ever seen, and made a great female foil for Zim, it's easy to see why.
 * THE MOOSE! Seriously. The Moose has it's own fanbase just for being so damn impressive.
 * And speaking of moose, Minimoose, who only appeared in one episode before the show got cancelled, makes regular appearances in fanart and fanfic, usually as the Woodstock to GIR's Snoopy. He's just so darn cute...
 * Another one-shot character with a large fanart following would be Foxglove the bat of Chip 'n Dale Rescue Rangers.
 * Tammy, from the same show. In fact, her mom, who is never even named, has gained a tiny fan following as well.
 * Schnitzel of Chowder. Almost all of the commercials for the show primarily feature Schnitzel as opposed to the titular character.
 * To a lesser extent, Gorgonzola has become somewhat popular on the internet, but this hasn't really had much impact on the series.
 * A lot of tertiary South Park characters have become incredibly popular with fanfiction writers: Craig, Tweek, Pip, Gregory, Christophe (aka "The Mole"), the Goth Kids. Perhaps the most baffling is Damien, the son of Satan, who has spoken in exactly one episode and appeared in the background in a few others. Searching for him on fanfiction.net produces five pages of results, or over a hundred stories.
 * Damien wouldn't be nearly as popular if slash fans hadn't noticed his interaction with Pip, another example of this trope, in the one episode he was in. If you look closely at those fanfiction.net pages, you'll see that nearly all of them are Damien/Pip fanfics. Which is even more baffling, considering that Damien set Pip on fire to earn the respect of the other boys.
 * The popularity of the Goth Kids might be because fangirls like to use them as an outlet for their own angst---which is ironic, because that's the kind of attitude the Goth kids are supposed to be a parody of, with them doing it pretty much just to stand out and look down on others. Especially awkward since only one of them has a canonical name, though on Fanfiction.net at least "Dylan" for the red-tinged Goth and "Ethan" for the tall one seem to be Fanon.
 * For a guy who is almost certainly gay and has only appeared in one episode and whose only relationship appears to be with Butters (meaning there shouldn't be much for fanfic writers to actually do with him) Bradley from "Cartman Sucks" has quite a few stories about him getting with Butters.
 * Brooklyn, Goliath's rawboned, beak-faced, Wangsty young second-in-command on Gargoyles.
 * Jinx has a pretty big fan-following in Teen Titans despite only appearing in 5 out the show's 65 episodes.
 * Red X appeared in two episodes where he wasn't just Robin's disguise but has a big fan following, largely for being a mysterious, Badass Chaotic Neutral Anti-Villain.
 * Argent. Despite only appearing for a short amount in two episodes, and subsequently being a very little developed character, there's a large amount of fanart for her, and several fanart groups on Deviant ART.
 * There's also Kid Flash, who also only appeared in two episodes. Probably helps that he and Jinx became an Official Couple.
 * The Grim Adventures of Billy and Mandy has Fred Fredburger. YES!
 * Jack O'Lantern is quite popular, despite appearing in only one movie.
 * Hoss Delgado. Nuff' said.
 * "MORBO OF Futurama DEMANDS RECOGNITION OF HIS POPULARITY."
 * "All glory to the hypno-toad!"
 * Zapp Brannigan, who often has the best lines in the show.
 * Also Zoidberg!
 * Calculon and his UNGODLY! ACTING! TALENT!!!
 * A few characters from Daria could stake claims to this, though Stacy Rowe is possibly the best example, as her popularity with the fandom was likely the reason why she got an actual, honest-to-goodness recurring subplot in season five, which, for any Lawndale High character not named Daria, Jane, or Quinn, was really quite a feat.
 * Daria's Cool Aunt Amy, despite only showing up in three episodes (one of which was basically a cameo). Daria herself was originally just a background character on Beavis and Butthead.
 * Odlaw from the Where's Waldo cartoon series seems more well-liked than Waldo himself. To a lesser extent, Woof could qualify as this.
 * Tom the fish from SpongeBob SquarePants spawned an internet meme of him saying "CHOCOLATE! CHOCOLATE!"
 * Squilliam Fancyson.
 * Old Man Jenkins.
 * Fred the "My leg!" guy.
 * Smitty Werbenyagermanjensen: HE WAS NUMBER ONE!
 * The Powerpuff Girls featured a one-shot set of villains in season one - the Rowdyruff Boys. They were flat, somewhat uncreative male counterparts to the three main characters. What's more, they were defeated by getting kissed. Mere days after the episode first aired, the internet was swamped with dozens of fanfics and fanart pieces devoted to them. Entire websites - exhaustive websites, full of art, episode transcripts and bustling forums - were created in their honor. The fans were almost unanimous in the desire to see the boys come back. After four years of demand, they finally returned in season five - given hints of personalities and very strange new hairdos.
 * Bunny only appeared in one episode, yet is a popular character.
 * The Simpsons: Apu is a good example of recurring Ensemble Darkhorse. First he started out as the typical Indian cashier, and then he got a few episodes centered around him. For Character Development, he even got a wife and eight children. He might also act as the Simpsons' Sixth Ranger, as seen in The Simpsons Hit and Run.
 * Also Milhouse, even before his memehood was disputed.
 * A popular one-time character is Linguo, Lisa's Grammar Nazi robot from "Trilogy of Error."
 * Also Hank Scorpio, a one-off character who was basically a Bond villain whose gimmick was caring greatly for his employees.
 * Both Troy McClure and Lionel Hutz - voiced by the late Phil Hartman - deserve a mention as well, especially the former - before Hartman's death, there were talks about a potential live action film featuring the character. It can't be just a coincidence that the retirement of both characters coincides with the point in the show's history when it developed a Broken Base.
 * Bleeding Gums Murphy only had a major role in two episodes and a number of background appearances in-between these before his character's death, but his role as a kindred spirit and mentor to Lisa is fondly remembered by older fans of the show (especially those who watched the first season). His death was one of the show's truest Tear Jerker episodes.
 * Professor Frink was introduced as a wacky Mad Scientist character who wanted funding for his death ray--which Grandpa Simpson talked him out of developing without even trying. He quickly became a regular character. He even had a website dedicated to him before FOX had it removed.
 * Disco Stu was originally just a one-shot character meant as a joke. Homer was selling a custom-made rhinestone jacket at a yard sale that said "Disco Stu" on the back. When Marge asked who it was, Homer replies "Well, it was supposed to say 'Disco Stud' but I ran out of space." He's since made several appearances.
 * The same goes for Cletus the Slack-Jawed Yokel and the baby with one eyebrow.
 * The late Frank Grimes appeared in only one episode and yet is one of the most memorable Simpsons characters ever.
 * Aquaman from Batman the Brave And The Bold. He's OUTRAGEOUS!
 * The Music Meister, despite only being the main villain of a single episode. Though, the fact he's voiced by Neil Patrick Harris probably helps. After the episode was out there was tons of fanart, and demands that he be incorporated into the DCU within minutes. The demand for the soundtrack was so high that they announced plans to release a soundtrack about two or three days after the episode leaked onto the internet, and said that if the show had a third season he would be back. (Unfortunately, he wasn't.)
 * Two-Tone from One Hundred and One Dalmatians: The Series, to the point that the fans would prefer she'd been the fourth main character instead of Spot.
 * Rebecca, from the episode, "De Village Elder", is also a character who gained a lot of popularity among the fans.
 * Angel from Lilo and Stitch: The Series, an intended one-shot who reappeared later due to popularity.
 * Charity Bazaar from Histeria! is stated to be the best character on the show by even people who hated it.
 * In fact, in the Histeria! fandom, the whole Kid Chorus seems to be more popular than the hosts (with the exception of Miss Information).
 * Foamy Mouthed Fanboy (otherwise known as Frothers, though most just call him Foamy.) from Avatar: The Last Airbender. Showed up twice, for about ten seconds. Has his own fan club.
 * Also Ty Lee. In the show, she really isn't as important or developed as her friends Azula and Mai. Yet her fanbase is huge. Of course, being cute helps.
 * She was popular during her intro for two obvious reasons as well as other things, but appearing in a bikini during "The Beach" practically skyrocketed her into this trope. It's pretty obvious why this wardrobe choice was able to make her so popular.
 * There's also Jun, which the creators even commented on. Likely why she has a reappearance in the Grand Finale.
 * Both Suki and Jet were meant to be one offs as well. Fan demand brought both of them back in substantial parts and Suki even
 * Although it's not exactly as much "popular" as "well-remembered", Koh. He barely had any plot-importance even the two times you see him (one was a flashback), but he's was just so damn creepy that he's become a frequenter of fanworks and Epileptic Trees all the way up to the end of the show.
 * The Cabbage Merchant!

"World's Biggest Fan: And when is Fifi going to get her own series?"
 * The Boulder.
 * The Clock King from Batman the Animated Series. Years after the series ended, everyone remembered that one villain who, based on his knowledge of all things timely, had memorized all of Batman's moves, nearly got him in a startlingly well-conceived Death Trap, and escaped capture by jumping off of a building, because "the 9:15 is always six minutes early!" After one reappearance in the series itself, his enduring popularity earned him a guest appearance over ten years later in Justice League Unlimited.
 * Harley Quinn was introduced as a goofy bit-player, but hit it off so well with both the writers and the audience that she became a regular and a Canon Immigrant.
 * The series was also responsible for the rise in the the popularity of villains like the Mad Hatter, Clayface, and Mr. Freeze, who until then were practically obscure to people who weren't into the comics. Special mention to Mr. Freeze's case, as his Backstory in the animated show was so well-written that was adapted into the comic book series and turned him in another memorable villain of Batman.
 * "Thriftie", an unnamed character with only one minute of screen time.
 * Roxie Rocket only appeared in two episodes (one of which was only a cameo) and yet has gained a strong enough following to become a Canon Immigrant.
 * Marlene the otter from The Penguins of Madagascar seems to be becoming this, likely due to being the most level headed member of the show and a possible future love interest for Skipper. King Julien the Ring Tail Lemur was also a popular enough character from the movie to earn a spot in the show.
 * In Animals of Farthing Wood the most popular character is Bold, Fox and Vixen's oldest son. After a reckless attempt on Scarface, he leaves White Deer Park to live his own life. He learns the hard way how to provide for himself, gaining a partially blind eye and a bullet in the leg. He struggles to earn the love of a vixen (Whisper), who only becomes his mate after finding out his father is a figure of local legend. He swallows his pride and takes her back to White Deer Park so she can have their cubs in safety. The injury in his leg ultimately kills him, but not before he knows his father is proud of him. And he only appeared in eight episodes of a three season series.
 * Ask anybody who's seen Gravedale High who their favorite character was. 9 times out of 10, you'll get Vinnie Stoker as the answer.
 * Roger from American Dad. This was probably inevitable given his diva personality.
 * Dark Danny from Danny Phantom gets this despite only appearing in an hour-long movie. There's a variety of fanfics where fangirls sympathize him despite his Complete Monster status.
 * Ghost Writer is another one-episode-only character that gets tons of fanart.
 * Clockwork, who only appeared in two episodes.
 * Ember McLain. Of course, she is a teen heavy metal star who's, well, really hot. In-universe, she's even powered by popularity.
 * The Fairly Odd Parents has three. The first, Norm the Genie, was a three appearance villain that became a Draco in Leather Pants among the fandom. The second is Ms. Doombringer, a highly competent fairy hunter that appeared in just one episode but has people asking for more. The final is Molly, a girl that showed up for one episode but already has shippers pairing her and Timmy together.
 * Also Remy Buxaplenty to some degree - he appeared in one episode to challenge and lose to Timmy in a duel, and pretty much disappeared after that. All the same he had a fairly significant following and a tendency to be shipped with Trixie Tang - who wasn't even in the episode he was in - and years later was brought back for a small handful of new episodes.
 * And quite possibly Dark Laser. Initially, he was a one off villain. Then he made an appearance in the fifth season as a continuity nod, but by the sixth season, he'd become a semi-regular, even having a major part in the season finale.
 * What, Timmy's Dad isn't mentioned? DINKLEBERG...!
 * Binky the Clown in Garfield and Friends. He made his debut in the Garfield Halloween Special a year before he showed up in the comic strip. In that special he was onscreen for only a minute, but it was easily the funniest minute in the entire special. He's only appeared rarely in the strip, but in the show, he was a semi-regular, even starring in the premiere episode. He even had his own little feature, "Scream Along With Binky." It helps to be on television where you can actually hear him say, "Heeeeeeeeyyyyyyy, KIDS!!!"
 * In Metalocalypse, a show about the five members of a death metal band, who emerged as the most popular character? Their manager, Charles Foster Ofdensen. Fending off an assassin and making said assassin stab himself totally helped.
 * And even he fails to live up to the standards of DOCTOR ROCKSO! THE ROCK AND ROLL CLOWN! HE DOES COCAINE!
 * The Deadpan Snarker computer with a British accent from Courage the Cowardly Dog.
 * Fred the Barber Half the show's references on this site are about him. He was the least dangerous but most memorable villain.
 * Di Lung. To the point where he would appear more frequently during the later seasons.
 * Katz is another example. His popularity may be the reason he appears more often than other villain on the show.
 * King Ramses' is quite popular despite the fact that many find his episode to be the scariest. In fact, the reason as to why most people assume he is scary is possibly an excuse to make him seem more popular.
 * Kitty and Bunny. And they're only One Scene Wonders!
 * Star from Balto is quite popular with the fans of the movie. "Circles are a good thing!"
 * Wolfie from Casper Scare School.
 * Also Poil from Casper the Animated Series. Despite only appearing in a few episodes, she probably has more fans than Casper and the Ghostly Trio combined.
 * Smokey from The PJs.
 * Who ever thought that an animated series would feature a crack addict (and a lovable one at that)?
 * Dukey from Johnny Test but then again many sidekicks turn out to be more popular than the main hero.
 * From Total Drama Island we have Deadpan Snarker Noah. His popularity is all the more astonishing considering his extremely limited screentime in season one - he appears in just six of the twenty-six episodes, has no lines in three of those six episodes, and has two words of dialogue in the entire second season, aside from the finale. In response to his popularity the producers added him to season three, with Chris introducing him as a "returning fan-favorite".
 * Likewise, Cody's popularity in season one is why he was given a major role in World Tour, even managing to.
 * Ezekiel, arguably the most minor contestant of all, also has a surprisingly large fanbase, although his hatedom might be just as large.
 * Also from Total Drama: Revenge of the Island, Dawn. Seriously, after the first trailer for the series aired, she had more fan art on deviantart than any of the other cast and was the first to have her own fan group there. Even now that the show has aired, she's still quite popular.
 * Misery is far and away the most popular character on the cheerfully-gothic Canadian cartoon Ruby Gloom. Her only conceivable rival is the title character, at which point it's kind of hard to draw a comparison.
 * Gene Khan in Iron Man: Armored Adventures. Yes, even after the season one finale and what he did during it. He is the Ensemble Darkhorse of the fandom. Two of the longest Fan Fics in the IMAA fandom focus on him. Fans like pairing him up with Tony and Pepper. The fan forums' Epileptic Trees tend to center around him quite often. His mother also gets discussed/written about quite a bit given that we only see her in a single flashback once.
 * Freddy from Back at the Barnyard.
 * Cad Bane of Star Wars: The Clone Wars earns this role as a Badass villain with a western motif as well as beating around The Scrappy Ahsoka Tano. Captain Rex has his fans too.
 * As does Admiral Trench, the Chessmaster spider who turned up, much to the surprise of Admiral Wullf who thought he was dead, made Anakin run behind the moon for cover, then bombed the planet to draw them out and deduced who was flying the retaliating stealth ship. When he died the first time it was at the hands of a special task force just for him and led by Jedi.
 * Embo, the bounty hunter. After appearing in only one episode. This video demonstrates why.
 * Savage Opress has proven to be quite popular, partly due to his resemblance to fellow Ensemble Darkhorse Darth Maul.
 * Despite his scant role in Code Lyoko, Clone William's calm idiocy and "adorable" personality made him a hit with fans- even moreso than William himself.
 * Rocko's Modern Life has the Cheese. He is the best character on this show, after all.
 * He is better than the Salami and Balony combined, after all.
 * Also, Dr Hutchison who was only a one time character that had so much appeal, that she married Filburt who was one of the main characters.
 * Filbert himself is an example of this trope. He started out in the series as a minor, nameless character that would appear every now and then, but eventually became one of the main characters.
 * Peaches, the ruler of Heck, who appears in two episodes.
 * Adventure Time has Marceline the Vampire Queen. She was already intended to be a recurring character, but after her first appearance she was already a fan favorite. She seems to show up more often now as a result.
 * Lumpy Space Princess. "Bunch of smooth poseurs."
 * Adventure Time with Fionna and Cake caused a massive influx of Marshall Lee and Lumpy Space Prince fans, even though they only appeared for about four seconds and didn't even have any lines.
 * "Fionna and Cake" in general. The episode got 3.3 million views, while most other episodes get 2 million something views. If your search "Adventure Time" on Deviant ART, you'll get nearly as much fan art of the gender-flipped characters as the regular ones, and fans have even made some of their own gender-flipped versions of characters that didn't have one in the episode. There's probably even quite a bit of FinnxFionna shippers out there. And these characters were just
 * The weirdest thing about it is that if you do a deviantART search on Adventure Time, the most popular piece of art that comes up is gender-swapped.
 * The Earl of Lemongrab is apparently turning out to be this. He only had about a minute and a half of screen time (so far,) but he managed to gain a small yet EXCEEDINGLY LOUD fanbase.
 * On Phineas and Ferb, Gretchen (the Fireside Girl with glasses) gets this sometimes, mostly because she was the first girl the boys' age to get a name other than Isabella, and thus became Ferb's designated love interest for anyone who didn't like Ferb/Vanessa. The fact that she is later revealed to be rather brainy (like Ferb himself) seems to retroactively justify this. The other Fireside Girls get this a bit too.
 * In the episode It's About Time! there's a kid who helps Candace sneak back into the museum after being thrown out for yelling. He only appeared in that one episode, and he probably doesn't even have a name, but he was such an interesting character that some fans want him brought back. Also, he stole a complete fossilized pterodactyl skeleton from the museum.
 * Kyle from Fanboy and Chum Chum, to the extent that several fans cite him as the only reason they watch the show at all.
 * Sigmund as well, even before he made his debut!
 * An example of a team of Ensemble Darkhorses are the Brotherhood of Mutants from X-Men: Evolution. Particularly Pietro 'Quicksilver' Maximoff, and Todd 'Toad' Tolensky. While they as a whole get it for their status as Ineffectual Sympathetic Villain, the Fan Dumb tend to be very touchy on this. While undoubtedly entertaining and easily popular, they have a habit of being latched onto by the crazier fans. Especially Avalanche and Pietro.
 * Canon Immigrant X-23 was so popular that she was brought into the comics after only two real appearances and a cameo in the finale, with a million fanfics dealing with her life - some very depressing, some comic, some just to be paired off with characters she never even interacted with, and most of the time she just becomes a Mary Sue..
 * The show has a notable exception among the franchise, Wolverine isn't the most popular character on the heroes side. There actually isn't just one in particular. The show was so well written than almost anyone could function as the Ensemble Darkhorse, and if you look at the fandom that's pretty much what happened, but special mention on the good guys side should go to Nightcrawler. This is about as close and any adaptation got to his orignal playful, charming, character from the comics.
 * Nightcrawler is easily the most popular male of the main cast, the most popular character in the show is Rogue, though, like the Brotherhood, for the wrong reasons, see Possession Sue.
 * Robert Mandell,creator of Adventures of the Galaxy Rangers, stated that he had set up the pilot episode and the inital story arc around Zachary, but then "Along came Goose".
 * Ed, Edd 'n' Eddy has Marie, the blue-haired Kanker. She has a much larger fanbase than any other girl in the show and is often considered to be the most attractive one, despite not being intentionally designed as such.
 * But what about Plank? Fans who have made stories focusing on that piece of wood make him out to be secretly an evil genius due to apparently being sentient and being only able to "talk" to Jonny. Also, there's a plushie of him.
 * Generator Rex has Breach, who gained a bunch of fans due to a combination of some Foe Yay with the main character, and being attractive while being delightfully creepy at the same time. It got to the point where the fandom had a collective freakout when she seemed to be killed off, then rejoiced when it turned out she was fine.
 * 21 and 24 (but especially 21 now) from The Venture Brothers They started off as nameless henchmen (numberless, too in the first episodes) to have more air time than the Monarch himself. In the latest season, 21, after he Took a Level In Badass, could arguably be called the leader of the Monarchs. The other henchmen refer to him a General 21. He is even putting the moves on Dr. Misses the Monarch, whom he has always crushed on.
 * An interesting case occurred during productions of Disney's Sleeping Beauty. The three fairies were originally intended to be minor supporting characters, with no names and no differences between them other than the colors of their clothes. The filmmakers became such fans of the characters as they developed that they wound up taking over the film.
 * And of course, the evil fairy, Maleficent, the villain of the movie, is also the most popular, well remembered character.
 * Despite the frequently horrifying content, the Peadofinder General in Monkey Dust is particularly popular. Something about the big hat and green skin...
 * On the villainous side of The Avengers: Earth's Mightiest Heroes, Grim Reaper won over a lot of the fanbase with his debut appearance- a big Crowning Moment of Awesome breakout. While callous, he's also an Adaptational Badass and Creepy Awesome, unlike his comic version who was pretty lame.
 * Ultron first appeared in episode 5 as an innocent prison guard. As the first season progressed, he gradually enterted the foreground while obtaining the knowledge that would turn him into the Killer Robot Marvel fans know and love. He finally turned against the Avengers in episodes 22 and 23, performing such feats as possessing Iron Man's armor, seemingly killing, and using stolen nuclear missile codes to try and wipe out all "flawed" life on Earth. Even though the Avengers defeated him in only two episodes, an unofficial poll deemed him the most popular villain by a longshot.
 * Doctor Doom won fans over even before his first episode premiered. His actual feats didn't disappoint either; he overcame six Avengers and the entire Fantastic Four in a battle, and found a Skrull among them even before they could. The end of the episode creates the impression that he'll come back, though not when or how frequently.
 * As Iron Fist and Luke Cage beat up thugs, cracked dry wit, and helped track down the thief of Hank Pym's Ant-Man suit, the viewers wished they could watch these Heroes For Hire kick even more ass in their own show.
 * Storm Hawks: Stork. Good freaking God, Stork.
 * Kim Possible: Word of God is that Dr. Drakken and Shego were originally just supposed to be a part of the show's rotating cast of villains, but became so popular with the fans that they were used more and more often.
 * Electronique was rather popular with fans, more than you'd expect from her single appearance. But then, she was a Baroness and Gadgeteer Genius with electrical powers, a short temper and a hammy accent from somevhere in zer centre of Europe, so she was a memorably entertaining character, and as a villain in Shego's hometown she had a connection to the fandom's favourite character.
 * Freakazoid had Candle Jack, a one off charact
 * Blinky Bill had adorable little Woobie Shifty Dingo and Furry Fandom Fetish Fuel Station Attendant Daisy Dingo.
 * Doug: Roger Klotz and his gang, the chief antagonists. Also, Doug's older sister Judy Funnie.
 * Maximus IQ from Atomic Betty : Despite him being a villain, people see him as a main character as well.
 * Appearing once in a series with Quarter Hour Short episodes, Ultraprison's Mistress is surprisingly popular among the Superjail fandom.
 * Although Ben 10 Alien Force and Ben 10: Ultimate Alien are both Contested Sequels, they have given us a fine Darkhorse in the form of Ra-GRK! "LET ME TELL YA SOMETHIN', WWW.TVTROPES.ORG! RATH IS THE BIGGEST Ensemble Darkhorse IN THE ENTIRE SERIES, AND DON'T YOU FORGET IT!"
 * Albedo, a Galvan who turned into a Palette Swap of Ben, is popular among the fandom, despite lack of appearances.
 * Megas XLR. The REGIS Mark V is the ultimate fighting machine! Unstoppable! Merciless! Glorious! No one is safe from the REGIS!
 * Fifi LaFume from Tiny Toon Adventures. She appears infrequently in episodes and only has 4 shorts of her own, but is by far the most popular character with the fandom, for obvious reasons, and many fans wish that she should have had a bigger role. Being a Ridiculously Cute Critter and a sympathetic character also helps. This is probably also why she got cameos in Animaniacs.
 * Lampshaded in ''Night Ghoulery".


 * Also, to a much lesser extent, Julie Bruin, who only appeared in one episode but is quite popular.
 * The Mayor from the Action League NOW shorts on Ka Blam!.
 * King Bob on Recess, for his hammyness and "Mundane Made Awesome" attitude.
 * Hustler Kid, escpecially with the female fanbase
 * Cornchip Girl, Butch, and Lawson also have sizeable fanbases.
 * Miss Grotke, for being a Moe Hippie Teacher with hints of Sensei-chan here and there (and was pretty popular among the show's older male fanbase)
 * Fillmore had a red-herring character in one episode named TQ in one episode; a stoic, Deadpan Snarker Zen student. Apparently, he really caught on with fangirls.
 * Carl from Aqua Teen Hunger Force.
 * Robot Chicken parodied this when Rick Berman (producer of Star Trek: The Next Generation) tried to create a character more annoying than Wesley Crusher. The response? "Kill Wesley. Keep Snirkles." Oops.
 * Out of all the many characters that were introduced when the Aladdin series started, the big fan-favorite was definitely Mozenrath, the young, snarky Magnificent Bastard with a tragic secret, in a world otherwise full of Laughably Evil, Smug Snake and one-shot Eldritch Abomination villains.
 * Wacky Weasel, a one-shot villain from Bonkers actually has a good ammount of fanart and screenshots on the internet.
 * Morph from X-Men was a supposed to killed while saving Wolverine from an ambush at the end of the series' opening two-part episode. But due to the unexpected popularity of the character he returned, and later had several episodes centering on him.
 * From Jem we have Stormer in the Misfits. Her popularity is fueled by her being the Token Good Teammate of the Misfits, albeit she is capable of having a nasty attitude from time to time. She's the overall creative force behind her band but she never gets credit for it, and usually winds up helping (secretly) the Holograms when she absolutely feels she needs to. Stormer has also been the only Misfit to be offered a place in the Holograms, but she turned it down because she felt the Misfits needed her more. Word of God has it Stormer's first loyalty is always going to be the Misfits regardless, which really only makes her more likeable; she sticks by her friends.
 * Tale Spin has quite a few One-Scene Wonder characters with fan followings, including cowgirl Clementine Clevenger (Wildcat's Love Interest in "Citizen Khan"), Princess Lotta Lamour ("The Road to Macadamia"), and Adventurer Archaeologists Katie Dodd ("For Whom the Bell Klangs") and Myra ("In Search of Ancient Blunders"). Don Karnage, the scourge of the skies, is extremely popular within the fanbase and even got his own solo outing in Raw Toonage.
 * Jackie Chan Adventures has one in Jade's (technical) Super-Powered Evil Side, the Queen of the Shadowkhan. Despite only showing up in one episode in Season 2 (and getting a brief mention by Tarakudo in Season 4), there are quite a variety of stories in which she regains the powers and/or personality of the Queen.
 * In Sym-Bionic Titan just about every minor character fits this trope. Notable examples include:
 * Tashy 497, a lovable squishy space squid who showed up in a single episode with the same name. Apparently, he was so adorable the fandom kept him, and now he has his own fanart, almost as much as anyone else, including the main cast. He often will make a cameo in other artworks, but never in series,  20 minutes screentime.
 * Memetic Rapist Xeexi. 2 minutes screen time.
 * Barb. She walks into their house on random, and has reached a supreme stalker status, even though she was only ever used to move the story along. Her stalker status came from her various intimate, and arguably sexual, encounters with Mr.Lunis. She's often depicted in fanworks as the creepy neighbor. So this is the one time where the fans keep a character IN character. 5-10 minutes screentime.
 * Jason. First came as an object of hate, and created the meme "LET'S GO BOMB JASON'S HOUSE!", after he was established as Ilana's love interest during the shows short run. Even though we have no idea how long that relationship would have lasted, and it had been established in Word of God that Lance wasn't going to fall in love with Ilana, fans still hated him for ruining their ship. Now he's depicted in various works as the timid guy Lance beats up on, even though he only showed up for a cumulative 5 minutes.
 * Mirabel. Mentioned because....there really is no reason why. She's just commonly mentioned. Went to the prom with Lance, then he left so she spent that time with Jason. Her popularity may have stemmed from people settling that Ilana was free again because Jason and Mirabel hit it off, even though that was never confirmed. minute and a half of screentime.
 * Kristin, the goth girl introduced in Ballad of the Scary Mary and asked out by Lance is Under the Three Moons. Because her potential was never completely reached, and because of her cool attitude, she became someone the fans noticed. Also rocketed in fandom for the same reason Jason is: She ruined the Lance/Ilana ship. Depicted in fanworks as a snarky, kickbutt, female Lance. Also popular because of an episode of Dexter's Laboratory, Eye Eye Eye's, where the little girl depicted looks like a younger version of Kristin. Now she's known as the Eye Eye Eye's girl. about 2 minutes of screentime.
 * The Eye Eye Eye's episode of Dexter actually made another character popular; Brandon. "Kristin" rand of with a brown haired boy with shining eyes, and he looks like a younger version of Brandon. And so the ship "Krandon" was born. His popularity also comes from his jerkish behavior towards Kimmy as his Ex. 45 seconds screentime.
 * It should be noted that both Titan and Dexter were created by Genndy Tartakovsky, justifying this assumption.
 * Todd has become popular due to a stellar performance by an avid RPer who took his little 30 second run and made an interesting character. Even though it was never said in the show, he says "fabu" alot in fanon, is bisexual, and looking for love.
 * Baron (arguably the biggest example of this on Titan's listings) from the episode Shadows of Youth has become popular enough to be shipped with Ilana, have his own fanfics, and many wanted him to show up again. In fanon, he grew up to be a sexy, yet confused, bastard who loves to torture Lance in his every day life, part of that being flirting with Ilana. He's actually blown up so much that him saying "I WAS SUPPOSED TO BE A PLOT DEVICE" has become a Memetic Mutation, and exploited for the fans to hold up their campaign. Part of the reason fans fight hard for this show is Baron, figuring out what happened to him, and the fact that you can't have such a jerk character who was depicted only as a child then never get the opportunity to show his later years and have no one wonder where he went, so his Darkhorsism is justified. 10 minutes screen time.
 * Mike Chan in "Roar of The White Dragon". Often depicted as the self centered, jerky, somehow sexy, Asian. Paired with Lance at times, even though Lance already outwardly expressed that he was in love with Mike's Car, but hated Mike. Might be popular because it was alluded that he would come back, but the show ended before he could. 12 minutes screen time.
 * His girlfriend, dubbed June by the forementioned RP'ers (There is an official RP that does show cases on CN's facebook page with a well written out script, that is why they are so acknowledged and important in this fandom)even though she never said anything. And that is what she is known for. Not saying anything. 5 seconds screen time.
 * Meat. Popular because he was voiced by the same guy as Patrick Star. His wacky antics and nonsensical dialogue made him popular, and is often depicted doing something silly and out of place for this show. Also depicted as Octus' best friend even though he only had about a minute of screentime.
 * The other cheerleaders. Monica (the black one) is known for only talking about how hot Lance is, Amber is known as Kimmy's closest BFF who's not all that bright (likely brought about on her from the fandom because she's blond) and obsessed with her weight. Justified due to her freaking out and thinking an airway would break because she had eaten a single fry at lunch, and Tiffany, who is best known for not being known. At one point, people only noticed Amber and Monica, but when people started scratching their heads to remember the other one, when she was remembered, they remembered hard. Various amounts of screentime, but no more than 10 minutes.
 * Zordrak and the Urpneys of The Dreamstone seem to hold a fairly dominant helping of the show's fanbase (though that may have been deliberate), however Urpgor in particular takes the cake. They may have caught on in later seasons, where he gets larger roles.
 * Skippy Adventures in Bushtown gives up Pos, the adorable possum cameraman.
 * As Cow and Chicken's humor made less and less sense, The Red Guy became the only reason to keep watching. He was so popular he was imported to I Am Weasel.
 * From Kids Next Door, Sector Z! After five minutes of screentime in the movie they won the hearts of a sizeable portion of the fanbase with their badassery. It probably helps that they
 * Ben 10 is a specific case in that the main character himself is technically an army of Ensemble Darkhorse. Indeed, Ben Tennyson being a Shape Shifter who can assume various alien forms, across the series he gets a lot of forms that are heavily popular amongst the fans even when not playing an especially major point in the plot or even having limited appearance:
 * The original series had XLR8, Ghostfreak and the other horror-themed aliens (Benwolf, Benvicktor and Benmummy), amonsgt other; To an extent, almost every alien in the original serie has his share of fans.
 * Though the new aliens started being contested by fans (and and not just the aliens) in 'Ben 10 Alien Force, most fans at least agree that Swampfire and Big Chill are cool. And even the most strident Alien Force haters usually love'' Rath.
 * While Ben 10: Ultimate Alien has been criticized for adding many Replacement Scrappies of old aliens, the five Andromeda aliens dubbed as "Team Awesome" by the fans are usually recognized as good aliens. The fact they were scanned from actual characters with each one their own stories probably help.
 * Aside from the aliens forms, several minor characters and villains in both series have become Ensemble Darkhorses. Those include Charmcaster, Lucky Girl (though this is actually Gwen is disguise), Kevin (who later was upgraded into a main villain and then a hero), Albedo, Darkstar... and let's not forget Paradox, who is probably as popular as Rath himself.
 * The Sword in the Stone is ''not' a movie about a boy and a wizard who turn into squirrels and said boy attracts the attention of a cheerful, overly friendly female squirrel who becomes the cute version of a Stalker with a Crush and wouldn't leave him alone, mistaking his actions for playing hard to get or his way of attracting a mate but is ultimately a Determinator set on making him love her back and earn him as a mate for life only to learn he's a human and run away in tears, watching the boy she fell in love with walk away forever to his home miles away. That's just 9 minutes of the movie, but with all of the fan art and fanfiction surrounding said little squirrel, you'd think those 9 minutes were a major importance to the plot.
 * Bubble Guppies gives us Nonny, the orange haired guppy that, as of the second season, gets less screen time than the others and is notorious for never smiling.
 * Stuffy the blue dragon from Doc McStuffins.
 * Might be the reason the Hex Girls have appeared in several Scooby Doo related media, despite pretty much no other characters, even relatives of the main cast, having that honor.