Canon Foreigner

When an established existing medium ventures into the Expanded Universe, writers will often rely heavily on familiar characters and past storylines from the official Canon to ensure that fans of the original material are happy. Unlike the original canon, however, an "expanded universe" adaptation also gives the writers freedom to introduce new, "never before seen" characters, as the production staff enjoys their newfound liberation from whatever codes and limitations ruled the original work.

Often, these new characters will be added to fill a particular need in the new story, and add some degree of novelty to attract readers/watchers. Frequently, they'll also fill some gap in the current cast, such as adding a female character to an all-male cast, or imposing some other element of diversity, be it racial, geographic, or simply personality. This can spark new conflicts and adventures that wouldn't otherwise occur under the limitations of the "conventional" cast and series format — one of the main points of "expanded universe" fiction to begin with.

Depending on how well the character fits into the adaptation or how much the fans like the character, Canon Foreigners can either be much beloved or much hated, and if popular enough, may be Ret Canoned into the official canon where they are known as Canon Immigrants.

Filler Villain is a Sub-Trope of this.

Compare Original Generation characters, who are Canon Foreigners to several canons at once in a Crossover plot.

See God-Created Canon Foreigner when this character comes from the original creator.

Anime & Manga

 * All seventeen of the Dragon Ball movies, apart from Mystical Adventure and The Path to Power, featured original characters who were never seen in the original manga, although Garlic Jr. from Dead Zone did appear in an anime-only story arc in the TV series, as did Gohan's pet dragon from The Tree of Might.
 * Bardock from the TV special: Bardock - The Father of Goku briefly cameos in the manga; several of his allies and enemies who starred in the special do not.
 * Ashil from the Shaman King anime.
 * And the Lily Five, who became surprisingly popular among the fans.
 * The Aliens and the Makaiju in the first arc of Sailor Moon R, the similarly themed Fiore in the Sailor Moon R movie and Perle & the villains from the Sailor Moon SuperS movie. Also Yūichirō, Rei's love interest.
 * Kiyone from Tenchi Muyo! was added in the TV version as a Straight Man foil for Mihoshi. She has since become one of the more popular cast members, but never featured in the original OVA canon, where her name is used for a completely different character.
 * She has a counterpart in the third OVA in Noike; the green-haired, no-nonsense former partner of Mihoshi.
 * She is also in the semi canonical Mihoshi Special (Which in canon is Mihoshi telling a story which may or may not be based on real events) and the movie Daughter of Darkness which takes place in the OVA continuity.
 * Kitazawa Ken, Professor Utonium's son from Demashita! Powerpuff Girls Z.
 * Sasuke Sarugakure, the ninja servant of the Kunō family in the Ranma One Half anime, is at least a semi-regular character who never appears in the original manga. On his first appearance, he did the actions originally done by Gosunkugi, a character oddly removed from the anime at first, and introduced much later. There are a number of other anime-only characters, but few of them appear in more than one episode.
 * Liu Kowloon, Eva Durix, Oni-Maru and Alexander the flying squirrel from the Virtua Fighter anime seires.
 * The Fatal Fury anime movies had Lily McGwire and Tony in the TV specials, as well Sulia Gaudeamus, Laocorn Gaudeamus, Panni, Hauer and Jamin in The Motion Picture.
 * The Art of Fighting TV special only had one, Ray. Sadly Ray wasn't long for this world, though with this movie he probably was better off.
 * Homura, the Big Bad of the second season of Gensoumaden Saiyuki, and his two henchmen, Zenon and Shien. Homura didn't make it to Canon Immigrant status, but original manga-ka Minekura Kazuya did write and illustrate an Omake chapter about him.
 * The characters Crys Mu, Dark Mu and Hattori Kinzo in the Teenage Mutant Ninja Turtles OVA series.
 * Li Mei-ling from Cardcaptor Sakura, as well as piles upon piles of new cards.
 * Lulu from Shugo Chara
 * Barasuishou, the second Big Bad of the Rozen Maiden anime, who replaces the manga's Kirakishou.
 * Nabeshin and Pedro (as well as every character in Pedro's storyline) in the Excel Saga anime.
 * The 2009 anime for Fullmetal Alchemist, Brotherhood, introduces a brand-new Anti-Villain known as Isaac MacDougal, the Freezing Alchemist, who mostly just exists to (1) establish the characters and their relationships to each other before they would appear in the manga's storyline and (2) drop metric shitton of Foreshadowing before any of it shows up in the manga storyline. Really an upgraded Filler Villain.
 * The 2003 anime version, due to its more divergent nature, had even more of these. The most prominent ones were Lt. Col. Frank Archer, Lyra,, and the show's versions of Wrath and Sloth.
 * The Sonic the Hedgehog anime OVA had three. Sarah, the President, and the old man Owl.
 * Cosmo and most of the human characters in Sonic X.
 * Street Fighter Alpha: The Animation has Dr. Saddler, Rosanov, Wallace, and Shun (Ryu's "brother"). The manga adaptation of Street Fighter II by Masaomi Kanzaki also has Po-lin and her brother Won-mei.
 * The 1986 Super Mario Bros. anime film has Princess Peach's fiancee, Prince Hal of the Flower Kingdom (Peach/Mario fans don't have to worry about him showing up in any future game).
 * Many of the star trainers from Pokémon Special are taken directly from the main game series (Blue herself existed as a Mythology Gag), yet Yellow and Emerald are the only ones with no canon video game equivalents.
 * And given the nature of the Pokémon anime, there are numerous recurring characters not based on any original game characters, the most notable being Jessie, James and Meowth.
 * Pokemon manga in general have many characters who aren't counterparts to any in the games.
 * Miyu Edelfelt from Fate Kaleid Liner Prisma Ilya is, thus far, the only character who doesn't have a counterpart of some sort in normal Fate Stay Night continuity.
 * The Slayers anime featured Zangulus in the first series, Martina in the second, Filia and Valgaav in the third, and Pokota in the fourth and fifth.
 * Yu-Gi-Oh! has many, but one of the most notable would be Noah Kaiba; the character would be the actual son of Gozaburo Kaiba (Mokuba and Seto's foster father), who conveniently died right before Mokuba and Seto arrived at the Kaiba manor. He also looks a lot like Seto, even though they're not blood-related.
 * Inuyasha has a few. Ayame, a wolf-demon girl and supposed bride-to-be to Koga; Akitoki Hojo, a past ancestor of one of Kagome's classmates. Kagome's friends, Eri, Ayumi, and Yuka, could also be considered as such. While they appear in the manga only one of them (Eri) is named and they hardly have any parts to play as opposed to the anime where they're used for many a filler.
 * Magic Knight Rayearth has Innouva (season 1), plus Nova, Debonair and Sierra (season 2).
 * Code Geass has several due to its various spinoff manga and video games, including literal Evil Twins Castor and Pollux from the Nintendo DS game; Rai, the protagonist of the Visual Novel Lost Colors; Mariel, Suzaku's Love Interest in Suzaku of the Counterattack; Nunnally's best friend Alice and the other Irregulars from Nightmare of Nunnally, and more.
 * The Gurren Lagann manga introduces Nia's eldest sister, Princess Straea, who was discarded many years ago only to have chosen to serve her father by running the all-women village for him, and now wants Nia to take her place.
 * Bleach inverts this with the Mod-Souls, who are introduced in the Anime Filler and stick around as barely-noteworthy assistants in Urahara's shop. The last noteworthy thing that we see of them is them is helping Renji defeat a filler villain.
 * Persona 4 The Animation has the minor recurring character Aika Nakamura. But since Persona 4 is getting an Updated Rerelease she might become a Canon Immigrant.
 * Traditionally there are four Saint Beasts as was the case in Angel Tales with Goh, Shin, Rey and Gai filling these roles. When Angel Tales spawned a rather different Spin-Off, Saint Beast, Judas and Luca were created to be the main characters and the Saint Beasts became six instead. Also, instead of the goddess, Zeus became the head god of heaven.

Comics

 * While Archie Comics' Teenage Mutant Ninja Turtles Adventures, was originally meant to be a Recursive Adaptation of the original cartoon, it eventually featured a good dozen original characters. The most prominent were allies Ninjara, Oyuki Mamishi, and Cudley the Cowlick; and villains Armaggon, Verminator X, Null, and Maligna.
 * And while we're on an Archie kick: in Archie Comics Sonic the Hedgehog, canon foreigners outnumber characters adapted from the games or the Saturday Morning cartoon.
 * Sonic the Comic (alternately known as Fleetway Sonic) also contained many canon foreigners, supposedly based on the various critters released from Badniks in the first Sonic game, such as Johnny Lightfoot (a rabbit) and Porker Lewis (a pig). It also included squirrel turned invincible Badnik "Shortfuse the Cybernik", and a whole legion of Mecha-Mooks known as "Troopers".
 * The rarely seen Sonic manga released by Shogakukan in 1992 also had some canon foreigners of it's own. Aside from the three main characters of the games at that time, it also featured Nikki as an ordinary version of Sonic, Nikki's family (Anita, Brenda and Paulie), Little John, Anton, Madd, Amy and Charmy.
 * A borderline, but accurate case: Campion Bond of The League of Extraordinary Gentlemen. When every other character, no matter how background or minor, is taken from a work of Victorian literature, it is a shock to find a main character that's completely original (albeit an apparent ancestor of James Bond).
 * Not quite: not all the works from which characters are derived are Victorian, or literature, and there are other Canon Foreigners, too, including other ancestors of established characters. A good example is an ancestor of The Dude who makes a brief appearance in The New Traveler's Almanac. More prominently, William Sampson, the League's cabbie isn't an existing character, although he is the father of the Wolf of Kabul, from The Hotspur.
 * Originally the creators of The X-Files comics were told they could not use the character of the Cigarette Smoking Man so they created a mysterious blonde woman to fill his role. Later the producers changed their minds and the comics were allowed to use CSM and the mysterious blonde quietly vanished. It is unlikely she will ever appear in any other adaptation of The X-Files.
 * The Star Trek comics produced by DC in The Eighties featured a plethora of original characters, until they were told to cease doing so. None of them have ever been heard from again.
 * The story I heard with that was that Roddenberry, basically pushed off actively supervising TNG after the first season, was given complete charge over the comics instead. Frustrated and beginning to see his final decline in health, he used his authority to x out any non-canon characters, a restriction that drove away Peter David, who was writing a memorable run on TOS comics at that point.
 * Peter David himself has managed to bring some of these characters back in his Expanded Universe novels. Star Trek the Animated Series was, for a time, considered non-canon, but that did not stop David from integrating M'Ress and Arex into crews in his Star Trek The New Frontier novels. The same series reintroduced comics-only character Nancy Bryce, who reflected upon her memory of fellow canon exile Bearclaw. The third member of their Lower Decks Power Trio, Klingon refugee and acting ensign Konom, however, is likely exiled forever, given that Star Trek the Next Generation established Worf as the first Klingon to become a Starfleet Officer.
 * As with Star Trek, the Star Wars comics added dozens if not hundreds of new characters. Two of them -- Aayla Secura and Quinlan Voss (mentioned but not shown) -- actually make it Canon Immigrant status.
 * In the late 1980s, DC Comics did a Doc Savage series that centres around Doc being moved through time to the present day. The series included Doc's grandson and a team of new aides Doc assembled (as his original aides were now all old men). While interesting, these characters are unlikely to appear in any other version of the Doc Savage saga.
 * Disney Adventures ran a one-shot comic taking place after the original Toy Story. The story revolved around Speck, the puppy Andy got at the end of the movie. This was written years before Toy Story 2, which introduced his canon equivalent, Buster.
 * In DA's Darkwing Duck comics, there was a popular recurring villain named Fluffy, a super-intelligent housecat with a robotic suit of armor, who never appeared in the official canon.
 * The early Doctor Who comics had John and Gillian, the Doctor's other grandchildren, and other, less well-remembered companions. Doctor Who Magazine comics had Sharon (companion to the Fourth Doctor), Sir Justin and Angus "Gus" Goodman (companions to the Fifth Doctor) Frobisher (long-running companion to the Sixth, and briefly, Seventh Doctors), Izzy, Fey, Kroton (a rogue Cyberman) and Destrii (companions to the Eighth Doctor) and the Tenth Doctor has Majenta Pryce. Other comics have featured other companions. The comic in Doctor Who Adventures has Heather McCrimmon and Wolfgang Ryter as companions to the Tenth Doctor.
 * As well as companions, the DWM strip featured other recurring characters such as Max Edison and Colonel Muriel Frost. The latter might be a Canon Immigrant as "Major Frost" in "Aliens of London", in which case she's dead.
 * In the early 90s, Nintendo Power published a series of comic adaptations of whatever game Nintendo was hyping during the year. They published Super Mario Adventures (loosely based on Super Mario World) and The Legend of Zelda: A Link to the Past in 1992, Star Fox in 1993, and Super Metroid in 1994. Each comic took liberties with their source material by introducing new characters such as Floyd the salesman in Super Mario, Roam the archer in Zelda (who is incidentally an Expy of "Jet Link" from Cyborg 009), Fara Phoenix in Star Fox, and Armstrong Houston in Super Metroid.
 * Marvel loved to do this in the 1980s with their adaptations from other media. They seemed to enjoy introducing relatives to certain characters; fathers, sons, and brothers, ESPECIALLY brothers! In Dino Riders, Questar's brother pops up at the end of the 1st issue. In Defenders of the Earth, The Phantom has to confront his evil brother. G.I. Joe has two examples: The Baroness blames Snake Eyes for killing her brother.... And oh yeah, Cobra Commander has a son.
 * Various Transformers comic lines have loads of this, introducing original Transformers, like Primus, Scrounge and Jhiaxus that never were in the toylines before. And with the... eagerness Transformers fans display, many of these characters reach Canon Immigrant status, earning their own toylines.
 * The Mortal Kombat comic by Malibu, in addition to featuring drastically different portrayals of canonical characters (the original Sub-Zero and Baraka were both good guys, while Kitana is romantically involved with Kung Lao instead of Liu Kang), also featured several characters exclusive to the books such as Hydro, a Lin-Kuei ally of Sub-Zero and the twins Sing and Sang. Most of them were written so that the characters could use their Fatalities without killing any of the major characters from the games.
 * Ninja Turtles again: IDW's Teenage Mutant Ninja Turtles book, while focusing mostly on characters brought in from other TMNT incarnations, has also introduced a handful of new characters of its own, such as cat mutant Old Hob, who was mutated at the same time as the turtles; and Alopex, a mutant artic fox.
 * The DC Comics Powerpuff Girls book introduced the Powerpunk Girls, who are popular in fan fiction.
 * Agent Phil Coulson, from the Marvel Cinematic Universe, has recently been imported into the mainstream 616 comic continuity

Films -- Animation
""Here's my card! I'm not in the book, but I'm at your service!""
 * Lola Bunny in Space Jam would eventually become a Looney Tunes Canon Immigrant, with analogues in Baby Looney Tunes, Loonatics Unleashed, and The Looney Tunes Show.
 * Wybie in the Coraline movie.
 * Astro Boy 2009 has loads -- Zane, Widget, Grace, Sludge, and Orrin, to name the more appealing ones -- as well as replacing Cathy with Cora.
 * The Doorknob in Disney's Alice in Wonderland is the only character in the entire movie who was not originally created by Lewis Carroll.
 * The Night Fury dragons are actually found only in the film adaptation of How to Train Your Dragon. In the books, Toothless was much smaller and looked more like a Terrible Terror dragon than a Night Fury dragon.
 * Thumper and Flower in Bambi.
 * Gopher in Disney's Winnie the Pooh cartoons. This gets (stealth) lampshaded:

Films -- Live Action

 * Rachel Dawes from The Dark Knight Saga.
 * Batman movies tend to do this a lot since the character has had few romantic ties in the original material, while filmmakers still wanted to insert a Girl of the Week. Because of this, both Batman Forever and Batman and Robin had love interests that never existed beyond their respective movies.
 * The minor love interest Julie Madison in Batman and Robin was actually a character in the comics back in the early 1940's. Perhaps more a case of bringing back a character burdened with What Happened to the Mouse?.
 * Ross Webster and Gus Gorman from Superman III.
 * The Lord of the Rings films added various tertiary characters as well as additional individually identified bad guys. To this end, one of the Uruk-Hai in Fellowship of the Ring was given more importance and called "Lurtz". Similarly, Gothmog fills this role in Return of the King. Technically, the latter was in the book, but only mentioned in passing, and it's unspecific whether he's even an orc. The movie expands on this by making him a big nasty orc with what appears to be Proteus Syndrome.
 * And of course, we can't forget Figwit, who is an Ascended Extra in the movie but non-existent in the book.
 * It's possible that Figwit could be one of the present, but forgotten people at the Council of Elrond, like Erestor.
 * Figwit has now been retconned into Lindir, a very minor but canonical Elf from the book, with a return (preturn?) appearance scheduled in the upcoming The Hobbit movie.
 * The Hobbit duology is also confirmed to have a Canon Foreigner in the character Tauriel; a female Wood-Elf played by Evangeline Lilly, put in to make sure the film has at least one female character.
 * Yet another Teenage Mutant Ninja Turtles example; as in the original cartoon, they outnumber the actual canon characters. Tatsu, (TMNT I and II), Tokka, Rahzar (TMNT II), all the introduced characters in TMNT III and Max Winters (TMNT IV) are the most notable.
 * The Death Note movies added a female police officer named Sanami as an Affirmative Action Girl. There's also Light's girlfriend from the first movie.
 * The talking shrunken heads in the Knight Bus scene from Harry Potter and the Prisoner of Azkaban.
 * And the train station diner waitress in Harry Potter and the Half-Blood Prince.
 * Nigel is this... sort of. He's a Composite Character for the Creevey brothers, but he's still original to the films. Okay, he's basically Dennis Creevey, but at least the name is original.
 * The Owl in Irwin Allen's 1985 Alice in Wonderland is a character that does not appear in the original Lewis Carroll novel.
 * Tom Sawyer and Dorian Gray in the film adaptation of The League of Extraordinary Gentlemen, although those characters were alluded to in the original material, they were never seen and certainly were not main characters.
 * Also the film features an Expy for the Invisible Man because they couldn't get the rights to the H. G. Wells character.
 * Alice, in the Resident Evil films, to the point of overshadowing the canon characters.
 * Agent Myers from Hellboy (the sequel ditches him).
 * Clue the movie had Wadsworth the butler.
 * Robert Hammond, a U.S. Senator and the father of Hector Hammond, in the Green Lantern film.
 * In Supergirl, all of the major characters save Supergirl herself, her parents, Jimmy Olsen, and Lucy Lane.
 * Another (sort of) exception is Principal Danver. In the comic book, the Danver are Supergirl's foster parents on Earth. Perhaps this character (or one of his relatives) was supposed to adopt Supergirl in a sequel that was never made.
 * The Blade movies have many:
 * In the first one, Blade, Whistler, and Deacon Frost were the only comic characters. Blade's quasi-love interest and all of the named vampires were created for the movie.
 * In the second, Blade and Whistler were essentially the only comic characters to be featured in the movie. While there was a team called the Blood Pack in the original material, the individual members featured in the movie were new.
 * Like the Blood Pack, the third film featured a team of vampire hunters that were lifted from the comics called Night Stalkers, but Hannibal King was the only member taken from the comic series. Whistler did not have a superhero daughter and the rest were completely new characters. Also, while Marvel Comics did have a version of Dracula that has fought Blade many times, this film featured a version that was taken in a different direction.
 * Aunt Millicent in the 2003 version of Peter Pan.

Literature

 * Although, like the comics, the Star Trek Expanded Universe novels were forbidden to use original recurring characters in the late '80s-early '90s, those restrictions were gone by the late '90s and the modern novels are given a lot more leeway for Canon Foreigner characters, and there are whole book series that aren't based on the shows and are populated mostly by Canon Foreigners or Ascended Extra characters (e.g. Titan, Vanguard, Corps of Engineers, IKS Gorkon, and even Department of Temporal Investigations).
 * In spite of their popularity and critical importance in the Star Trek Expanded Universe, neither Captain Calhoun nor Elias Vaughn has ever been featured in canonical Star Trek.
 * Although one major character created for the Star Trek Deep Space Nine novels set after the series was intentionally based on a certain extra who was only seen from the back in a canon episode.
 * Virgin Publishing's New Adventures range of novels for Doctor Who created a number of new companions for the Seventh Doctor, including Bernice Summerfield, Roz Forrester and Chris Cwej. Virgin's Missing Adventures had Grant Markham, a short-lived companion to the Sixth Doctor. BBC Books' Eighth Doctor Adventures range had Samantha Jones, Fitz Kreiner, Compassion, Anji Kapoor, and Trix MacMillan.
 * Innumerable new villains have occurred in the Doctor Who Expanded Universe. One, Faction Paradox, the Evil Counterpart to the Time Lords, spun off into its own sub-universe of audio plays, comics and novels. They began in novels.
 * Hotblack Desiato and Disaster Area in The Hitchhikers Guide to The Galaxy and subsequently the TV version of The Hitchhikers Guide to The Galaxy, were created to replace the sequence with the Haggunenons in the radio series, which was mostly written by John Lloyd, and therefore Douglas Adams didn't feel was "his".

Live Action TV

 * Girl turtle, Venus de Milo from Ninja Turtles the Next Mutation. A Canon Immigrant, sadly she's not.
 * Gaius of Merlin, who plays the mentor role now that Merlin himself is a teenager. Apparently they didn't feel like using Blaise, who was Merlin's actual mentor in the original myth.
 * Chloe Sullivan, of Smallville. Curiously, she is the only member of the original cast other than Clark to be on the show for all ten seasons.
 * Jack McGee from The Incredible Hulk. A really prominent example in that he's a canon foreigner who has been worked into a very well known catch phrase.
 * Kivaara, a tiny Kivat for the world of Kamen Rider Kiva and Kamen Rider Abyss, a shark-themed Rider for Kamen Rider Ryuki, both appear for the first time in the series' Crisis Crossover, Decade.
 * How much you consider Power Rangers an adaptation of Super Sentai is variable (depending on the season. You get some that are all their own and just borrow some fight footage, and some that are shot-for-shot remakes.) but in addition to non-sentai supporting casts, Power Rangers Lightspeed Rescue has the Titanium Ranger, a Sixth Ranger that doesn't exist in any form in the original series, which it is otherwise quite similar to. The Spirit Rangers may or may not count (the characters existed; that storyline and their getting shiny suits didn't.)
 * Power Rangers RPM has an attack with the wheels of the suits that didn't appear in Go-onger.
 * Except that it becomes Canon Immigrant in Gokaiger. No sign of the Burst Attacks yet, though.
 * Pretty Guardian Sailor Moon has loads of stuff. First there was Dark Mercury and then later Luna gained a human form, Sailor Luna. Unfortunately a lot of fans bellyache about Sailor Luna when she was a massive improvement on Chibi-Usa, who we'd have got otherwise!
 * Cameron Phillips and Derek Reese from The Sarah Connor Chronicles don't exist as far as the Terminator movies are concerned.
 * Insofar as we can call hundreds of years of legend "canon", the 1980s series Robin of Sherwood introduced the idea of including a Saracen to Robin Hood's outlaws, a figure that was popular enough to be included in Kevin Costner's Prince of Thieves and again the BBC's 2006 Robin Hood. The latter television series also introduced original characters Isabella (Guy of Gisborne's sister) and Kate (Locksley village girl) as Affirmative Action Girls after Marian and Djaq (who ironically, was the Saracen) were written out.
 * Xena: Warrior Princess functions as something of a Canon Foreigner to Classical Mythology. Her story takes place as the same time as Hercules: The Legendary Journeys, and featured the same Greek Gods, placing her squarely in the same area as the actual mythical Hercules.
 * Ros the whore in Game of Thrones, who serves equally well as Ms. Fanservice and The Watson, for especially thorny bits of exposition. George RR Martin has said he intends to give her a cameo in a later book, so she may soon get promoted to Canon Immigrant.
 * Alton Lannister, who may or may not be a renamed Ser Cleos Frey.
 * Talisa Maegyr, who replaces minor character Jeyne Westerling as Robb Stark's love interest.

Radio

 * The Big Finish Doctor Who audio plays had Erimem (companion to the Fifth Doctor), Evelyn Smythe (companion to the Sixth Doctor), Hex and Raine Creevey (both companions to the Seventh Doctor), Charley Pollard (Eighth and later, at least from her point of view, Sixth Doctor companion), C'rizz, Samson and Gemma Griffen, Lucie Miller, and Mary Shelley (all companions to the Eighth Doctor).
 * The Adventures of Superman introduced Jimmy Olsen, Inspector Henderson, Kryptonite and the names "Daily Planet" and "Perry White."

Tabletop Games

 * Whenever Clue comes out with an expanded version or spinoff based around Boddy Mansion (as opposed to say, Star Wars or The Simpsons) it seems traditional to add a bottle of poison as a weapon, as well as the appearances of Madam Rose, Sgt. Grey, M. Brunette, and Miss Peach as extra characters.
 * The mage/planeswalker Jodah in Magic: The Gathering was created by Jeff Grub for the novelizations of the plot of The Dark and the Ice Age cycle of books, created in 1999 (where the sets were created in 1994-5). He'd prove popular enough to get an Avenger card in Planar Chaos.

Theater

 * The Most Happy Fella, adapted from the straight play They Knew What They Wanted, built the comic Beta Couple of Cleo and Herman out of whole cloth, and gave Tony a sister Marie to object to his marriage. (In the original play, the objector is the Catholic padre; also, Amy jokingly refers to herself at one point as 'Cleo', playing off Antony and Cleopatra.)
 * Several characters in As You Like It (which was Shakespeare's adaptation of the Thomas Lodge novel Rosalynde), most importantly Touchstone and Jaques (of "All the world's a stage" fame). The rest of the Canon Foreigners in the story are all related to them in some way: Jaques, being a cynical philosopher, gets a scene where he plays off the idealistic, music-loving "Amiens", while Touchstone's subplot necessitates the inclusion of his love interest, "Audrey, a country wench", a country priest named "Oliver Mar-Text", and "William", Audrey's ex-boyfriend.

Video Games

 * Star Wars Galaxies introduced the Force Sensitive Village of Aurilia, Vader's failed apprentice Mellichae, The Meatlumps and their King to name a few. These canonical additions, among many others, have been cited in other Star Wars mediums.
 * Another Star Wars canon foreigner, Kyle Katarn is perhaps one of the most prominent video game-based canon additions from the Jedi Knight series who has spawned his own books and action figures.
 * The original characters in the Street Fighter EX series are owned by Arika, the company that developed the game, instead of Capcom. When the developers realized this, they retconned the backstories for Doctrine Dark, Pullum Purna, and Garuda to distance them from the canon Street Fighter cast (for example, Garuda, who was originally a demon created by the Satsui no Hadou, was now a manifestation of evil energy). Blair Dame and Allen Snider were also put in a non-Capcom related fighting game called Fighting Layer.
 * There's also Captain Sawada from both versions of the Street Fighter: The Movie game, as well as Blade and his palette swaps from the arcade version.
 * Apple in the Saber Marionette J game (Japan-only).
 * Joey La Rocca, Big Pussy Bonpensiero's illegitimate son in The Sopranos Road to Respect
 * Cyber Spider from the Bucky O'Hare arcade game.
 * The Teenage Mutant Ninja Turtles video games by Konami managed to avoid this for most parts, but there have been a few exceptions:
 * Aska from the SNES version of Tournament Fighters is probably the most notable example. She was basically created to fill in the gap as token chick, since the other females in the game were the final boss Karai and Damsel in Distress April O'Neil (though she did fight in the Genesis version). However, early builds of the game shows that her name was originally going to be "Mitsu", who was the heroine in the third live-action movie.
 * Sisyphus the mutant beetle from the Genesis version of Tournament Fighters was never in any other TMNT media, although its easy to think otherwise due to the number of anthropomorphic characters that were introduced to the toyline in later years.
 * Tora and Shogun Warrior from the NES port of Teenage Mutant Ninja Turtles the Arcade Game added to serve as bosses to the two NES-exclusive extra stages.
 * The various third-party Mega Man productions add characters that would never be seen again -- all of the bosses from the PC games (.EXE renamings and coincidentally same-named bosses in later games notwithstanding), several characters from the Ruby-Spears cartoon, Akane and Yuuta from the OVA, Dreamwave's three "boss characters", etc.
 * The insidious House Ordos from the Dune RTS games by Westwood Studios.
 * Turned on its head in The King of Fighters 2002 Unlimited Match: the new character Nameless was created specifically to take the place of K9999 from KOF 2001, who was such a blatant ripoff of Tetsuo Shima that SNK Playmore had trouble using him in later games.
 * Reika Kirishima, one of the playable characters in Shikigami no Shiro III, was originally the star of her own Laserdisc and Sega CD game called Time Gal.
 * Mew Ringo from the PlayStation Tokyo Mew Mew game.
 * Wolfduck was a villain that only appeared in the Darkwing Duck video game.
 * The Metal Gear Solid canon excludes all the original characters from Ghost Babel and the Acid games. If you wish to go further, there's also Twin Shot, one of the replacement bosses from the NES version of the original Metal Gear, as well as John Turner and Nick Myer, Snake's FOXHOUND comrades from Snake's Revenge (as well as the "Metal Gear 2" mecha from the same game).
 * Teliko and Venus from the Metal Gear Acid games did, however, make cameo appearances as playable characters in the canon game Metal Gear Solid Portable Ops. In that game, they were described by the other characters as 'aliens'.
 * Definitely Vermon CaTaffy and Higharolla Kockamamie from the NES Metal Gear games. Although neither character actually existed to begin with.
 * One of the more extreme examples would be Nicole-458 from Dead or Alive 4, who doesn't appear in any work from the Halo universe she comes from.
 * Her number also doesn't fit with the canon, as there were only 75 SPARTAN-II candidates (although their numbers are from the original list of 150), out of which only about 30 "graduated". All SPARTAN-IIIs have a letter before their number (e.g. Lucy-B091).
 * In Batman: Arkham Asylum, Batman meets in the titular asylum canon foreigners Frank Boles, doctor Young, and Quincy Sharp.
 * Scarface the World Is Yours has Felix and The Sandman.
 * The Godfather: The Game has such characters as Monk and Frances Malone, "Jaggy" Jovino and The Trojan.
 * The Oppositio Senshi in Sailor Moon: Another Story. Evil counterparts to the Inner Senshi and Moon.
 * Ezekiel Holloway and Atticus Thorn in The Haunted Mansion game.
 * Spider-Man: Shattered Dimensions has a few, mostly in the form of the Hammerhead from the Noir universe, the developers said that he felt like a perfect fit (he did fit quite well), 2099 Hobgoblin, as well as, there's also the DS versions, which have Noir Calypso, and 2099 Silvermane.
 * Mana Kirishima of the Neon Genesis Evangelion game Girlfriend of Steel. A Third Option Love Interest introduced to shake up the existing Shinji/Asuka/Rei Love Triangle, Mana was a Captain Ersatz mish-mash of the two existing girls -- Rei's gentleness mixed with Asuka's extroversion. She has mantained good popularity with the fandom since, to the point she became part of the cast of the AU manga Shinji Ikari Raising Project.
 * 2nd Impression, a lesser known Evangelion game for the Sega Saturn, had Mayumi Yamagishi. She was the Meganekko before Mari came around.
 * In her Resident Evil novelizations, S.D. Perry introduced Trent, a renegade member of the Umbrella board of directors. His role was to pull strings from behind the scenes, assisting the heroes while sabotaging Umbrella's plans.
 * The two original Resident Evil novels, Underworld and Caliban Cove, were written back before the release of Resident Evil 3 Nemesis. Two of the characters introduced therein, John Andrews and David Trapp of the Exeter S.T.A.R.S. unit, have a small fan following and occasionally appear to this day in fanfiction.
 * All the main characters in Discworld Noir. Canon characters such as Gaspode and Nobby Nobbs are limited to secondary roles. There is certainly no indication in the books that Lewton, or even the profession of Private Detective, exists.
 * The Simpsons Arcade game gives us all the bad guys in the game except for Mr. Burns, Smithers, the wrestler boss and the drunk boss.

Web Original

 * Donovan Corbett in Street Fighter the Later Years
 * Lewis Lovhaug is the White Zeo Ranger.
 * The Richard E. Grant Ninth Doctor from the Doctor Who web animation Scream of the Shalka, and his companion Alison Cheney.

Western Animation

 * The King of this trope would have to be Sonic the Hedgehog. The Sonic the Hedgehog series, affectionately known as SATAM, has the most memorable ones. Princess Sally, Bunnie Rabbot, Rotor the Walrus, Antoine, Uncle Chuck, and Snively became amazingly popular.
 * It's worth noting that the Freedom Fighters were originally based roughly off the small captive animals of the original games, even retaining their western names. However the concept was revamped before production and only a redesigned Sally Acorn (aka "Ricky") remained (though Rotor and Bunnie are arguably based off of Joe Sushi and Johnny Lightfoot respectively). Interestingly some of the Freedom Fighters (including the remodelled Sally for the show) cameoed in Sonic Spinball and were intended to be playable characters in canned titles, making for a somewhat complex Canon Immigrant.
 * Then there are Loads and Loads of Characters from Adventures of Sonic the Hedgehog, such as Prof Von Schlemer, McHopper, and Wes Weasley.
 * Also, almost the entire cast of Sonic Underground.
 * Both Teenage Mutant Ninja Turtles cartoons are the absolute kings of this trope, with dozens of these characters per series (a trend that continued for each added alternate adaptation made from the original comic book, as seen above). The most notable ones are Krang, Bebop and Rocksteady from the Fred Wolf cartoon, and Cody Jones, Agent Bishop, and Hun from the 4Kids series.
 * Hun later made it into a comic.
 * Spyke and Jerk Jock Duncan Matthews from X-Men: Evolution.
 * There's also a similar character named Spike who has a minor role in the live-action film The Last Stand.
 * Harry Grimoire of the ill-fated Darkstalkers cartoon.
 * Red Claw, Gray Ghost, Baby Doll, Roland Daggett, Kyodai Ken, and H.A.R.D.A.C. from Batman the Animated Series, plus Harley Quinn, Renee Montoya and Lock-Up, three successful Canon Immigrants.
 * The Gray Ghost is now a Canon Immigrant as well.
 * Ethan Bennett, Chief Angel Rojas, the Kabuki Twins, Temblor, and Scorn (but not Wrath, who was just very obscure) from The Batman. Seeing as Ellen Yin is inspiredBy Ellen Yindel from The Dark Knight Returns with Race Lift, she doesn't count.
 * Bruiser the Betelgeusian berserker baboon from the Bucky O Hare and The Toad Wars animated series.
 * Bluster Kong and Eddie the Mean Old Yeti from Donkey Kong Country.
 * Also, Captain Scurvy and Kong Fu.
 * Godzookie from the 70s Godzilla.
 * Eugene and Amani from The New Archies.
 * Indira "Indy" Daimonji and any villain who wasn't Electro, the Lizard, the Kingpin, Kraven, or Silver Sable in Spider-Man: The New Animated Series.
 * Gopher from the Disney version of The Many Adventures of Winnie the Pooh. He Lampshades this constantly -- his Catch Phrase is "I'm not in the book!"
 * Darby, Christopher Robin's Suspiciously Similar Substitute in My Friends Tigger and Pooh.
 * Kessie the bluebird. Introduced in a few episodes of The New Adventures of Winnie the Pooh, before becoming a regular character in The Book of Pooh.
 * Lumpy the Heffalump as well.
 * The Geek, a female child companion to Sam and Max Freelance Police, was created for the kid-friendly cartoon series. She was, however, created by the creator of the original comic books, with a light dash of Executive Meddling: originally he created The Geek as a male character, intended to make the series more kid's-TV-friendly, but when the network suggested Max be made female, he opted to make The Geek female instead. (A much more acceptable compromise.)
 * Blade's mentor, Whistler, in Spider-Man: The Animated Series, where his two main functions are to exposit about Blade and vampires and to convince Blade to trust and cooperate with the other heroes.
 * In fact, Whistler was created for the animated series and reused in the movie, and is an interesting example of canon foreigner existing in two mediums without becoming a full Canon Immigrant.
 * Skeeter from Muppet Babies.
 * While Skeeter has never appeared as a Muppet proper, she did appear in the "Muppet Teens" series of books, which was basically the Muppet Babies as teenagers..
 * Literally three quarters of the characters from the Super Mario Bros Super Show, The Adventures of Super Mario Bros 3, and Super Mario World cartoons have never been (and likely will never be) seen in the games. Most notably Oogtar and every other caveman character inhabiting Dinosaur Land in Super Mario World, every character based off a movie or story in Super Show, and every single character from the 'real world/Earth' in the first two cartoons.
 * Justice League and Justice League Unlimited used a bunch of characters who split the difference between Canon Foreigner and Expy:
 * Hro Talak is basically Hawkman, only evil. Except he can't be Hawkman, because the real Hawkman appeared in a later season.
 * Galatea is basically Power Girl, except she's a clone of Supergirl rather than an Alternate Universe counterpart. And she's evil.
 * The Ultimen are basically the Wonder Twins and the other original "ethnic" characters from Superfriends, only competent. And they're clones created by the Government Conspiracy.
 * The Justice Guild is basically the Golden Age Justice Society of America (with a little bit of Adam West as Batman for flavor).
 * Devil Ray is practically Black Manta, only he's a nemesis of Wonder Woman instead of Aquaman (who could not be used in the later seasons due to the unsold Aquaman pilot).
 * And in a cross-company example, the Justice Lords are versions of the JLA who became corrupted by their abilities and all but conquered Earth for "the greater good", only to be betrayed by their Batman. In other words, the Squadron Supreme.
 * For The Fairly Odd Parents, the Copper Cranium and the Gilded Arches show up only in the Crimson Chin webtoon. Arches later appeared in a video game. King Oberon, Queen Titania, and the Shadow only appear in the video game Shadow Showdown
 * Melissa Duck, from Baby Looney Tunes (technically, she's not the same Melissa from The Scarlet Pumpernickel cartoon).
 * Eva Skinner and about ten other one-off characters are introduced in the Code Lyoko novels.
 * The Legend of Zelda animated series had several of these, including Zelda's father King Harkinian, the fairy Spryte, and quite literally every other character to appear who wasn't Link, Zelda, or Ganon.
 * While Spryte herself didn't become a Canon Immigrant, the idea of Link having a fairy companion began here, and has been seen in most games.
 * Young Justice introduced a new Aqualad that was adapted to the comics before the show even aired. There's also the villainous organization called The Light, though it remains to be seen if this applies to its members (those since revealed are major DC Universe baddies).
 * Artemis seems to be one of these to anyone without much knowledge of the (fairly extensive) DC Universe. She's really an adaptation of Artemis Crock, the minor comics villainess Tigress.
 * Teen Titans had a metric ton of these. Most of the time they were to act as supporting characters or the Monster of the Week. A small handful (Mas y Menos, Billy Numerous, Cinderblock) managed to make it into the comics.
 * Superman: The Animated Series had quite a few with Volcana, Luminus, the Preserver, Sgt. Corey Mills, General Hardcastle, Detective Kurt Bowman, Darci Mason, Angela Chen, and Unity. Mercy Graves and Livewire started here and became Canon Immigrants.
 * Heroes On Hot Wheels was actually based on a French comic book called Michel Vaillant. The characters of Frank (Michel's younger brother), Hanna (Frank's photographer girlfriend), Quincy (Team Vaillante's mechanic) and Fox (one of Team Leader's racers) were not in the original comics.
 * Green Lantern the Animated Series has Razer, the new Red Lantern.