Minimalist Cast

The Minimalist Cast happens when the only characters that appear at all onscreen are the main characters. No supporting characters, no extras, no guest stars.

There may be ghost characters, who never appear onscreen but still exist for the main characters. Or there may be a Companion Cube, especially if this state of affairs is expected to last an entire series.

This is rarely pulled off successfully in long running serial material. Even Gilligan's Island -- a show whose premise was designed for this -- got guest stars. But sometimes it can be made to work. Serials which ordinarily feature more characters may restrict themselves to a Minimalist Cast for a one-off Bottle Episode.

In non-serial material, it is more easily arranged, as then The Law of Conservation of Detail no longer fights against the Rule of Drama or the First Law of Metafictional Thermodynamics. Note that the limited number of characters in no way guarantees their immortality; a Dwindling Party in these situations can be very frightening.

The Minimalist Cast is the essence of monologue-plays. Compare with Minimalism. See also Beautiful Void. The inversion is Loads and Loads of Characters. By definition, any work with a Minimalist Cast is also one where The Main Characters Do Everything, but these two tropes are still mutually exclusive.

Anime and Manga

 * Bakemonogatari only has about a dozen named characters. A few of them (such as Hitagi's father, or Koyomi's sisters) might seem less significant, but they only appear for actual significant interaction. Furthermore, there are no walk on extras at all (unless you count blurred and censored images in some flashbacks). In place of extras, they sometimes show a sort of person-shaped cut-out. It gives an eerie sort of feeling, considering things take place in what should be crowded places, and gets particularly creepy when you realize that every character in Hajikuji's opening are cloned extras of Hajikuji herself.
 * The only people we ever see in Angels Egg are the little girl with the egg and the young warrior with the cross-shaped riffle. Apart from them and couple of ghostly fishermen who can't really be considered characters, the highly-detailed world the two live in is completely deserted.

Comics

 * 1980s comic strip Arnold (created by Kevin Mc Cormick) only featured three characters: the titular character, his friend Tommy, and their teacher Mr. Lester. In the end of the strip's run a fourth character, Arnold's baby brother, was seen, but that's it. All other characters shouted from off-screen.
 * Most of the stories from The Fox and the Crow comic books in the '50s and '60s featured only the two Funny Animals from the title. Even in the few ones where some other characters appeared, it was for only a few panels and always as non-recurring extras in incidental roles.

Fan Works

 * For the most part, Potter Puppet Pals has only Harry, Ron, Hermione, Snape, Dumbledore and Voldemort. And Neville, played brilliantly by a squash.
 * When fans requested a puppet of Draco, the puppet Harry literally held a puppet version of Draco.
 * Most of the Silent Ponyville Chronicles have this trope, with the first installment including only Pinkie and Twilight. Being based on Silent Hill (see below) will do that.

Films -- Animation

 * Wallace and Gromit: A Grand Day Out and The Wrong Trousers had a cast of only three, and only Wallace spoke.
 * The Disney Princess franchise only composes of ten characters within said franchise (although with some exceptions, however). They originally wanted more than that, but then they learned the awful fate of 1985's The Black Cauldron upon the franchise's debut. The villain franchise, on the other hand, consists of every single animated Disney (and Pixar) villain to date.

Films -- Live-Action

 * 127 Hours: There are a couple of people for short parts at the beginning, and a family of hikers at the very end. The rest of the film is entirely focused on Aron.
 * Alien only features the seven crewmembers and, obviously, the alien.
 * Similarly, The Thing is centered entirely around the twelve members of the Antarctic research team. Aside from the two Norwegians in the opening scene, a corpse found in the Norwegian camp, and a few people seen for a few seconds in a pre-recorded game show, there is nobody else in the movie.
 * The Breakfast Club features the five kids in detention, the janitor and the principal (the kids' parents briefly appear at the beginning).
 * Gerry has Gerry and Gerry. Some other people are seen in the background but nobody else.
 * Dinner for One has two characters.
 * The film Moon by Duncan Jones has a grand total of two main characters: Sam Bell and GERTY. There is technically Sam's wife, but she is only seen in pre-recorded messages and a short dream sequence. Similarily, any other characters involved only appear in recorded messages from Earth. Nonetheless, Sam and GERTY are the only people to appear in person.
 * Timecrimes.
 * The 1968 film Hell in the Pacific features an American pilot (Lee Marvin) and a Japanese navy captain (Toshiro Mifune) marooned in a desert island during World War II. They're the only characters in the film.
 * The 2001 independent film Tape, based on a stage play, features Ethan Hawke, Robert Sean Leonard, Uma Thurman and nobody else.
 * Similarly, Neil Labute's 2003 film The Shape of Things was made from his stage play of the same name. Like Tape, the only characters to have speaking parts are the four characters of the play -- portrayed by the same cast too!
 * The House of Yes features five characters. There is a brief shot of a restaurant where we see three or four extras and that's about as expanded as it gets.
 * Night of the Living Dead
 * Buried is a good example: Ryan Reynolds is the only actor we see.
 * Akira Kurosawa's Rashomon has eight actors. Nine if you include the horse.
 * The 1972 film adaptation of Sleuth has only three characters. In his review of Sleuth, Roger Ebert
 * After the opening shot, the rest of Alfred Hitchcock's Rope takes place inside one apartment. The only characters we meet are the apartment's residents, their maid, and their dinner guests, a total of nine people (and the movie begins with one of them getting murdered).
 * 12 Angry Men. At the beginning, other people (such as the defendant and the judge) are briefly shown, but for the rest of the film, we only see the twelve jurors.
 * I Am Legend. Three humans. One dog. Millions of Go.
 * The Happiness Cage has only seven characters excepting two brief scenes at the beginning and end. Unsurprisingly, it was based on a play, but the clastrophobia is also an effective part of its theme.
 * The Disappearance of Alice Creed. Two kidnappers. One girl. Have at it.
 * Exam. Eight  characters in a room, plus the silent and immobile guard and The Invigilator who only shows up twice.
 * Cube.
 * Hard Candy.
 * Other people are about at the start and end of Cast Away, but for the majority of the film it's just Tom Hanks and a volleyball.
 * The only characters in Zathura are the protagonists, except at the very beginning and end when their father is around.
 * Lo has Justin, Jeez, April, and Lo.
 * Carnage by Roman Polanski features only four actors, with the exception of a few extras in the intro and epilogue, as well as a few voices heard over the phone.
 * Antichrist's plot involves only the principal couple, He and She, with their son dying early in the film and any other brief characters having their faces deliberately blurred.

Literature

 * Agatha Christie's And Then There Were None. Ultimately, ten people are on an island in this house after being sent a letter, and one by one, they start to die off.

Live-Action TV

 * Doctor Who did this way back in 1964 with a slightly surreal two-part serial "The Edge of Destruction".
 * When an episode was cut from the previous story and "The Mind Robber" was expanded from four to five episodes, its first episode became this. There was no budget (even by Doctor Who's notoriously low standards) for additional cast, props, costumes or even sets. The only resources available was the standing TARDIS control room set, the 3 leads, the robots that would appear later on in the story and a large empty stage painted white. Surprisingly it worked.
 * If the above implies that "and robots" doesn't disqualify an episode for this, then "The Girl Who Waited" counts as one of these. It features only the three main characters, some robots and a disembodied voice-interface. The cast list is the shortest of any new-series Doctor Who episode.
 * "Horror of Fang Rock" has the Doctor, Leela, seven guest characters and a single alien monster.
 * "The Doctor's Wife" has only eight characters, one of whom is The Voiceless, and two who die in the first half.
 * Irish sitcom Dan and Becs: two characters, whose total onscreen time together amounts to maybe one minute, out of two full seasons.
 * Degrassi Junior High didn't really have extras, because everyone you see was a character who would get an episode of their own.
 * The Red Dwarf episode "Marooned" principally takes place on a crashed spaceship, and focuses on Lister and Rimmer, with the rest of the main cast only appearing at the beginning and end.
 * Red Dwarf as a whole was based all around this concept, seeing as the whole premise was three guys lost in space millions of years after humanity's extinction.

Radio

 * Lum and Abner, although there was always the (very rare) exception.

Theater

 * Sleuth: The original 1970s version had only two characters onscreen, and was famous for it.
 * The play Two for the Seesaw has a cast no larger than the number in its title.
 * The play The Fourposter features one married couple. No other characters appear. When it was adapted into the musical I Do! I Do!, the cast of characters was not expanded into the typical musical comedy ensemble and chorus -- indeed, it was not expanded at all.
 * The play Same Time Next Year, is restricted to a single a courting couple.
 * The Australian play Ruby Moon appears to have Loads and Loads of Characters,
 * Several David Mamet plays, notably Speed-the-Plow, Boston Marriage, and American Buffalo.
 * Edward Albee's Who's Afraid of Virginia Woolf? has only four characters.
 * The Glass Menagerie, which has just four characters.
 * 'Angels in America' is an interesting example - while there's a fairly large cast of characters, there's an extensive and symbolic doubling scheme enforced that makes it a pretty tight show. The mini-series follows this and Hilarity Ensues.
 * No Exit features four actors on one set, one of whom is a One-Scene Wonder.
 * Waiting for Godot has four main characters and one cameo.
 * Master Harold and The Boys manages to get by with exactly three actors, a restaurant, and a black man's ass.
 * Speaking in Tongues has nine characters, played by four actors across three acts, plus a few Ghosts. The film adaptation Lantana subverted this by turning a few of the Ghosts into more significant characters.
 * The Mousetrap, by dint of everybody being stuck in a snowstorm and the entire play taking place in a single room.
 * I Love You, You're Perfect, Now Change has only four actors--two male, two female, just enough to hit all four vocal ranges. It helps that the show does not have a plot as such and is instead a series of vignettes.
 * Educating Rita features Frank and Rita as the only characters, although The Movie adds more.
 * Faith Healer by Brian Friel has one set and three characters, and there's never more than one character onstage at any given time.
 * Patrick Süskind of Perfume fame has written Der Kontrabass (The Double Bass). One set, one character, one giant success on German theaters.
 * Jason Robert Brown's The Last Five Years has two actors total. Even better, there's only a couple of songs when they're even on stage at the same time.
 * Samuel Beckett's Krapps Last Tape has a cast of one, an old man listening back to a tape recording he made earlier.

Video Games

 * Silent Hill is fond of this trope, most games containing a handful of characters amongst a lot of monsters. Isolationism is as strong theme throughout the series.
 * The first game has five or six characters (depending on whether or not Cheryl's infrequent appearances qualify her as a character), one of whom.
 * Silent Hill 2 has five characters, one of whom.
 * Silent Hill 3 has four characters total.
 * Silent Hill 4 has a surprisingly high number of eight, but four are dead soon after they're encountered and one is little more than a Continuity Nod.
 * Silent Hill Downpour has less than a dozen characters to populate a whole realistically sized city, with sprawling ghettos and subways, and the vast majority of those characters are enigmatic manifestations of the city. However, there are a few more characters in flashbacks, and lots of haunted houses with detailed histories and motivations behind their ghosts, so it feels like there are slightly more characters than are actually there.
 * Portal has two characters (one of them a Heroic Mime, the other a disembodied voice) and the Companion Cube, plus a few robotic Mooks.
 * The sequel adds two more characters, one of whom died years ago and is only heard from recordings.
 * The Stanley Parable has just Stanley and the narrator, although two of the endings introduce a new character.
 * Bastion, unless you count the Ura who are human, and have a role in the plot, but don't have any lines or characters amongst them aside from Zulf and Zia.
 * The only characters that appear at all in Shadow of the Colossus are: the unnamed protagonist, Mono (who is dead), Dormin, Emon, and Emon's (three) henchmen. Your Mileage May Vary on wether Agro and the colossi count as characters.

Web Animation

 * Homestar Runner may be the only work to successfully use both this trope and Loads and Loads of Characters, as the central world revolves around twelve main characters, with a small number of recurring extras and minor characters, but there are also Alternate Universes, "pseudocharacters", and fictional TV shows and video games.

Web Comics

 * Furmentation rarely shows more than a few characters, some of whom have no knowledge of another's existence.
 * Count Your Sheep. Only the five main characters appear. Even as they're talking to one of the few other characters to be mentioned, said character remains out of view. Occasionally a comic or two is from this character's point of view.
 * Dinosaur Comics, Though some characters "appear" offscreen. From time to time, we meet a head-only Batman due to the creator's interest in the character.
 * Fleep. Our protagonist is a man in a phone booth. The only other characters are a woman two booths over (only shown for a single panel), and a handful of voices on the other end of the phone line.
 * The Book of Biff takes this to its logical extreme. Not only is the Biff himself the only character to appear on-panel, the comic has no dialogue whatsoever, meaning that other characters are mentioned at best.
 * Garfield Minus Garfield' removes every other character but John for an ultimately creepy and sad effect.
 * Superego has only the ten characters who are trapped in an Abandoned Hospital in the middle of an abyss.

Western Animation

 * Any old theatrical cartoon series, despite having dozens of available characters in their recurring cast, will mostly have just one or two main characters and at least one antagonist in any individual cartoon. The Wile E Coyote and The Road Runner cartoons are a good example of this: no character other than Wile E. and the Road Runner appear. Sometimes the series character will be the only one on screen, such as many of the early Pink Panther shorts, or the Goofy "How-To" cartoons, where even the ones with team sports will have Goofy as every player.
 * Ed, Edd 'n' Eddy. Throughout the show's ten-year run, the cast of characters never expanded beyond twelve people. No background characters or adults ever appeared, and even when a school was added to the setting in later seasons, no additional kids appeared. There were a number of slight exceptions, such as Santa Claus in the Christmas special, Ed's Not-So-Imaginary Friend, and small body parts of adults appearing in a few episodes, but the rule was finally, truly broken for the first and only time in the Grand Finale movie, where.
 * The Backyardigans: We only see the five young Funny Animal friends.
 * Muppet Babies. Even in their imaginations, there are rarely any additional characters.
 * In the second season of the Redwall cartoon (based on the novel Mattimeo), the show migrates towards this. Slagar the Cruel captures most of the Abbey's young ones and adds them to his band of slaves, but midway through the season, he inexplicably only has the main characters in chains. Nowhere along the line does he sell any slaves; they're just gone.
 * The original Fireman Sam had a cast of ten main characters. One wonders how they make a living in Pontypandy.
 * Almost every short on Ka Blam!
 * Kaeloo is a particularly serious offender, having only four characters. While it could be argued that the seemingly sentient plants and the random sheep that pops up every now and then might count, they're still little more than props in terms of how they're used.
 * "The Farnsworth Parabox" episode of Futurama was designed as this, featuring only the Planet Express crew and their alternate counterparts as characters. This was in contrast to The Devil's Hands are Idle Playthings, in which the animators tried to fit in every character who had appeared in the series, as it was suspected that it would be the series finale.
 * The Bremen Avenue Experience is a series of shorts about a Funny Animal Garage Band. Most of the shorts feature only the four bandmates; the only guest star is the father of one of the band members.
 * The My Little Pony Friendship Is Magic episode "Party of One" only has the mane 6, Pinkie's pet alligator Gummy, Spike and Mrs. Cake, and the last two are only in one scene each, leaving only 7 characters in this episode. Not even any background ponies showed up.
 * The Bottle Episode "Look Before You Sleep", aside from a handful of background ponies in the opening seconds, only contains three of the mane cast.
 * "Stare Master" has Fluttershy, Twilight, Rarity, and the three Cutie Mark Crusaders, along with some chickens and a cockatrice.
 * "Baby Cakes" mostly only has Pinkie and the Cake twins, along with brief appearances by Mr and Mrs Cake and the rest of the mane six.
 * The 2009 reboot of Strawberry Shortcake.
 * In Jelly Jamm, there appears to be only seven people ON THE ENTIRE PLANET.
 * Zig and Sharko has a grand total of four characters.
 * Samurai Jack has multiple episodes where Jack is almost alone throughout its entirety, such as "Jack and the Monks".
 * The typical Ruby Gloom episode only features characters seen in the intro. Exceptions tend to become recurring characters in their own right or are related to Misery.