Sanguine: the cheerful, light-hearted, impulsive Imoen.
Choleric: the hot-headed, highly motivated, rage-harnessing Large Ham Minsc.
Melancholic: the cautious, sarcastic, grieving widow Jaheira.
Phlegmatic: the easy-going yet reserved Yoshimo.
In Blaze Union, the first five party members: Garlot (choleric), Jenon (melancholic), Medoute (phlegmatic), Siskier (sanguine), and Aegina (eclectic). And after the party dynamics suffer an upheaval, things shake down like so: Gulcasa and Leon (choleric), Nessiah (melancholic), Baldus (phlegmatic), Emilia (sanguine), and Aegina is... still eclectic.
Catherine, in terms of Vincent and his three bros that he hangs out with at the Stray Sheep. Orlando (choleric), Jonny (melancholic), Vincent (phlegmatic), and Toby (sanguine).
The Colour Tuesday: Alex is the hotheaded driver of the story (choleric). Kyle is the determined and selfless (melancholic). Bella is a slightly airy Cloudcuckoolander (sanguine). Chadd, the last permanent cast member, is a born follower (phlegmatic).
The Napoli Family in Delicious: Emily (melancholic), Evelyn (choleric), Edward (phlegmatic), and Angela (sanguine).
The Love Interests in Dragon Age II: Isabela (sanguine), Merrill (choleric), Anders (melancholic), Fenris (phlegmatic with a dash of melancholic).
The party in Dragon Quest VIII: Hero (phlegmatic), Yangus (sanguine), Angelo (melancholic), and Jessica (choleric).
The four playable characters of Drakengard, though at times they muddle about with their humors, tend to fall into distinct ones: Arioch (sanguine), Caim (choleric), Leonard (melancholic), and Seere (phlegmatic).
In Eroge! Sex And Games Make Sexy Games, we have Nene (Melancholic), Iori (Plegmatic), Momoka (Sanguine), and Kisara (Choleric).
In ClockUp's Euphoria, we have Kanae (Melancholic), Rinne (Plegmatic), Rika (Sanguine), and Nene (Choleric).
Fallout: New Vegas: NCR (Choleric), Caesar's Legion (Sanguine), Mr. House (Melancholic), Yes Man (Phlegmatic).
Fallout 4: Minutemen (Sanguine), Brotherhood of Steel (Choleric), Institute (Melancholic), Railroad (Phlegmatic)
Applies to the faction leaders too. Maxson is the driven hard charging choleric, Preston is the sociable sanguine, talking to everyone, Desdemona is the phlegmatic who acts as the Railroad's Team Mom, while Father is the cold logical melancholic.
The unprincipled accomplice, plus Big Bad quartet (counting a Big Bad from USN scenario): repentant accomplice Reiji Sakata (phlegmatic), Driscoll (sanguine), mole genius Olson (choleric), Patrick Wingar (melancholic), and Koichi Sakata (eclectic).
Gears of War's Delta Squad are like that: Marcus Fenix (choleric), Damon Baird (melancholic), Dominic Santiago (phlegmatic), and Augustus Cole (sanguine).
Grand Theft Auto IV: The four main characters fit: Brucie (choleric), Niko (melancholic), Little Jacob (phlegmatic), and Roman (sanguine).
Grand Theft Auto V: The Main Characters Epitomise all the Temperaments each. Trevor (choleric), Michael (melancholic), Franklin (phlegmatic), Lamar (sanguine) and Lester (eclectic).
The female leads of the visual novel G-Senjou no Maou are a picture-perfect example: Haru (choleric), Mizuha (melancholic), Tsubaki (phlegmatic), and Kanon (sanguine).
Due to the author being interested with the subject, MARDEK RPG does this. The author believes everyone has a primary and a secondary temperament, though. Perhaps the clearest ingame example is Legion: a construct created by an inventor. It was animated with dark magic, with the inventor saying the incantation - due to his stuttering, though, four souls entered the body instead of one - one for each temperament.
The major Mario & Luigi antagonists: Cackletta, Princess Shroob, Bowser (choleric); Fawful (sanguine), Dark Star (melancholic), Antasma (phlegmatic), Elder Princess Shroob (eclectic).
Mario (choleric), Luigi (melancholic), Starlow (sanguine), Prince Dreambert (phlegmatic)
Big Massif and his Hooraw disciples: Sorrow Fist (melancholic), Beef Cloud (phlegmatic), Heavy Zest (sanguine), Thunder Sass (choleric), and Big Massif himself (eclectic).
Mass Effect 2 has the starting four. Shepard (choleric), Miranda (melancholic), Jacob (phlegmatic), and Joker (sanguine).
Mass Effect and Mass Effect 3 squads are often comprised this way: Shepard and Javik(choleric), Garrus and Liara (melancholic) and Tali and EDI (phlegmatic). Likewise, James and Ashley (sanguine) and Kaiden (neutral phlegmatic).
The four council races also fall into these types. Humans are the impatient git'er'done cholerics, Turians are the rigid, structured melancholics, Asari are the diplomatic consensus seeking phlegmatics, while the Salarians are the always inventive, always curious sanguines.
Mega Man (Classic) series: Rock/Mega Man (phlegmatic), Proto Man/Blues (melancholic), Forte/Bass (choleric), Roll (sanguine), and Duo (eclectic).
The Robot Masters from Mega Man Powered Up: Fire Man and Oil Man (choleric), Guts Man and Time Man (melancholic), Cut Man and Ice Man (phlegmatic), and Elec Man and Bomb Man (sanguine).
Mega Man Battle Network: Dex and his Navi GutsMan.EXE (choleric), Chaud and Glyde.EXE (melancholic), Mayl and MegaMan.EXE (phlegmatic), Yai and her Navi Roll.EXE (sanguine), and Lan (eclectic).
Mega Man X Maverick Hunters of X5 onward: The fast-action Anti-Hero Zero (choleric), the conscientious defender X (melancholic), the father-figure Signas (phlegmatic), the flamboyant Axl (sanguine), and Douglas (eclectic).
Lady reploids of X8: Alia (choleric), Palette (phlegmatic), and Layer (eclectic).
The lone X-hunter (in his own right), X2's X-Hunters, and the Big Bad Sigma: Vile (super choleric), Agile (melancholic), Serges (phlegmatic), Violen (sanguine), and Sigma (eclectic).
Capcom never made clear whether classic Rock/Mega Man is the same Mega Man as X. If they are the same, Mega Man underwent a major temperament change. note Some may argue that the melancholic side to him simply got brought to clearer light as Mega Man got infused with human feelings.
Combo Ensemble counting the Four Guardians and the data-storing boss: The leaderly and loyal Phantom (eclectic), the indeterrable and Trigger Happy Fefnir (chol-sang), the virtuous and serious Harpuia (mel-chol), the calm-but-playful Leviathan (phleg-mel), and the Gadfly Maha Ganeshariff (sang-phleg).
Other bosses in 1st game: Copy-X (chol-mel) note a copy of X, but not quite the same temperament, and a lot less mature and Herculious Anchortus (phleg-sang).
Bosses in 2nd game: fiery Phoenix Magnion (choleric), Hyleg Ourobockle and Poler Kamrous (melancholic), Burble Hekelot (phlegmatic), electric Panter Flauclaws and Elpizo (sanguine), and Kuwagust Anchus (eclectic).
X-Series enemies holographed by Phoenix Magnion in Zero 2: Vile (choleric), Agile (melancholic), Bit (phlegmatic), and Colonel (sanguine).
MetroidPrime 3: Corruption: Samus (eclectic), Rundas (choleric), Ghor (melancholic), Gandrayda (sanguine), and most other allies (phlegmatic).
The main members of Diamond Dogs in Metal Gear Solid V: Big Boss (aka Venom Snake) & Quiet (phlegmatic), Revolver Ocelot (melancholic), Kazuhira Miller (choleric), Paz (sanguine), Huey Emmerich (eclectic).
Judging by their programmed natures, the Pac-Man ghosts:
Sanguine: Blinky (cocky, always chases)
Choleric: Pinky (chases and ambushes)
Melancholic: Inky (cautious)
Phlegmatic: Clyde (indifferent and random)
Intentionally invoked in Planescape: Torment. In the end game, you meet up with three copies of yourself, who are the good incarnation (melancholic), crazy incarnation (sanguine) and pragmatic incarnation (choleric). The character of the protagonist depends on how you've been playing him, but he does start out as phlegmatic.
The Major Circuit in the same game have; Piston Hondo (choleric), Bear Hugger (sanguine), Great Tiger (phlegmatic), and Don Flamenco (melancholic).
And the World Circuit have; Bald Bull and Aran Ryan (choleric), Soda Popinski (phlegmatic), Super Macho Man (sanguine), Mr. Sandman (melancholic), and Donkey Kong (eclectic).
Also, in "Super Punch Out", the Special Circuit follows this trope, albeit a bit less straight; Narcis Prince (choleric), Hoy Quarlow (phlegmatic), Rick Bruiser (sanguine), and Nick Bruiser (melancholic).
Sonic (Choleric): He's the leader of the gang. Driven by his own strong sense of justice, he can be very impulsive and most likely to take action should a problem present itself. He's quick-witted, easy-going and loyal to his friends. To his rivals and enemies, he can be an extremely condescending smart aleck. He has his moments of being arrogant and narcissistic, but is nonetheless a cool individual who’s always there to save the day.
Tails (Phlegmatic): He's the technician of the gang, his intelligence rivals that of Dr. Eggman's. He's very friendly, upbeat and humble, but can be very touchy and prone to self-doubt at times. He can also be naive and a blabber-mouth, which can greatly irritate his friends. Nonetheless, he's driven to chart the course and guide his friends.
Knuckles (Melancholic): He's the muscle of the gang and Sonic's former rival. He's stubborn, very short-tempered, and terribly single-minded. He's a driven individual who takes his duties as protector of Angel Island, along with the Master Emerald, very seriously. Only problem is that he can be very gullible, naive and easily misled to the point that cunning individuals (like Dr. Eggman and Rouge) can easily get one over on him.
Amy (Sanguine): She's the leader of her own group (Team Rose) but sometimes resorts to going along with Sonic and his crew. She’s a cheerful and optimistic individual who can be very compassionate and overly concerned with other people's problems. However, she can be very aggressive, stubborn and temperamental. Because of those traits, she can come across as very overbearing and a nuisance sometimes (especially to Sonic).
The three member Team Dark has this dynamic whenever Eggman is included:
Eggman (Choleric): He's the former leader of Team Dark in Sonic Adventure 2. Despite possessing a high IQ, he's terrible at scheming, and is pretty immature. He's intolerant and very temperamental when things don't work out for him. On the flip side, he can be very clever and able to create almost anything in order to achieve his goals. He's extremely cunning and with a sufficient amount of planning, could be very successful at conquering the world... or at least, he could've been successful if it weren't for a certain blue hedgehog.
Rouge (Sanguine): She plays the role of the charismatic leader of Team Dark in Sonic Heroes onwards. She's flirty, mischievous, and sometimes can be very narcissistic. She relies on her skills and wits to get her way, although she can get very infuriated when things don't go the way she expects them to.
Shadow (Phlegmatic): He's cold, ruthless and sarcastic (even to his own allies). He's very tough-minded and arrogant, it would seem as if it's impossible for him to cooperate with anybody. He does have a soft side to him though (which he rarely shows) and can be a very loyal and reliable individual when he needs to be.
Omega (Melancholic): He, the last E-series robot Dr. Eggman created, is very aggressive and while he's focused on a particular goal, he lacks tact and relies on sheer brute force to get his way. He's snarky, very prideful of his abilities, and views himself as superior to all of Dr. Eggman's creations. His own arrogance rivals that of Shadow's to the point where they can easily get into fights with each other sometimes but nonetheless remain loyal allies. He harbors a grudge against Dr. Eggman for disabling him and vows to destroy him.
Star Wars: Republic Commando: The four Clone Commandos of Delta Squad are this. Delta-38, "Boss", is choleric, showing good leadership instincts. Delta-07, "Sev", is melancholic, being the Cold Sniper of the group and showing great care to place each round for maximum effenciency. Delta-40, "Fixer", is phlegmatic, being, as Taun We put it, "A pure and uncomplicated soldier." Delta-62, "Scorch", is sanguine, showing much enjoyment in blowing the CIS forces apart.
In Street Fighter II, the four members of Shadaloo: Balrog (choleric), Sagat (phlegmatic), M. Bison (melancholic), and Vega (sanguine).
The Four Apprentices of Master Goutetsu: Gouken (melancholic), Akuma (very choleric), Ryu (phlegmatic), Ken (sanguine).
The five party members in Super Mario RPG: Mario (sanguine), Mallow (melancholic), Geno (eclectic), Bowser (choleric) and Princess Toadstool (phlegmatic).
The major Paper Mario antagonists: Bowser (choleric), Sir Grodus (melancholic), Shadow Queen (phlegmatic), Count Bleck (sanguine).
Count Bleck's Five-Bad Band in Super Paper Mario: O'Chunks (choleric), Nastasia (melancholic), Mimi (phlegmatic, but with a good dose of Ax-Crazy), Dimentio (sanguine), and Count Bleck (eclectic).
The ATX Team in Super Robot Wars. At first the lineup is Sanger (choleric), Bullet (melancholic), Kyosuke (phlegmatic), and Excellen (sanguine). Later, Kusuha was drafted into the team as the eclectic. Later on, Sanger leaves, and Kyosuke takes on the choleric mantle; and when Lamia enters, she takes on the phlegmatic mantle.
Xenogears has the Neo-Elements: Seraphita (sanguine), Tolone (choleric), Dominia (melancholic), Kelvena (phlegmatic). The characters are also associated with the classical elements, but not quite the same ones traditionally associated with the temperaments; Dominia and Kelvena match up (earth and water, respectively), but Seraphita and Tolone are switched (the sanguine temperament is associated with air and the choleric with fire, but Seraphita is associated with fire and Tolone with air).