Adventure Time: Finn (sanguine), Jake (phlegmatic), Princess Bubblegum (melancholic) and the Ice King (choleric, though that might just be the crown messing with his head).
In Adventures of the Galaxy Rangers, The Series 5 Rangers are also a quaternity. The series actually has very few episodes where all four are heavily involved, mostly breaking the team up into groups of two or three.
The New Batman Adventures: Though they rarely all worked together in the same episode, there was still a four-person "bat family." Robin (Tim Drake) is sanguine; Nightwing (Dick Grayson) is choleric; Batman is melancholic (as if it had to be said; he basically defines the temperament); and Batgirl is phlegmatic. Catwoman was the back-up choleric; in one episode, she and Nightwing even team up because of their similar personalities.
And from Batman Beyond, we've got the Royal Flush Gang who also form a Five-Man Band with the robotic Ace, who doesn't have a personality so they fit both categories: Authoritarian King (choleric), conflicted Ten (melancholic), Queen — a proper lady who tries to keep the family united (phlegmatic), and fun-loving Jack (sanguine).
Beast Wars: The four main Maximals: Optimus Primal (choleric), Rattrap (melancholic), Rhinox (phlegmatic), and Cheetor (sanguine).
Codename: Kids Next Door: Numbuh One - Nigel Uno (melancholic), Numbuh Two - Hoagie P. Gilligan Jr. (phlegmatic), Numbuh Three - Kuki Sanban (sanguine), Numbuh Four - Wallabee Beetles (choleric), and Numbuh Five - Abigail Lincoln (leukine).
Dan Vs.: Dan (choleric), Elyse Jr. (melancholic), Chris (phlegmatic), Mr. Mumbles (sanguine)
Danny Phantom's four-member "Team Phantom" can exhibit these: Danny is choleric for good leadership skills, but highly emotional personality; Jazz (though not depressive) is melancholic for her kind-but-perfectionist persona; Sam is phlegmatic because she's a responsible Stoic Goth; and Tucker is sanguine for he's fun loving.
The Fashion Club from Daria: Quinn (sanguine), Sandi (choleric), Stacy (melancholic), and Tiffany (phlegmatic).
Daria's family: Quinn (sanguine), Helen (choleric), Daria (melancholic), and Jake (phlegmatic).
As far as Lawndale High School: Mr. DeMartino (choleric), Mr. O'Neill (phlegmatic), Kevin and Brittany (sanguine), and Mack and Jodie (melancholic)
Finally, there's Mystik Spiral: Trent Lane (phlegmatic), Jesse Moreno (melancholic), Max Tyler (choleric), and Nicholas Campbell (sanguine).
Grojband: Corey (sanguine), Laney (phlegmatic), Kin (melancholic), and Kon (choleric).
Also, Trina (choleric), Mina (melancholic), Kate and Allie (sanguines), and Nick (phlegmatic).
A good chunk of the classic Hanna-Barbera cartoons characters that are connected to the Yogi Bear universe fit this mold if you put them together (think of all of the main characters in Yogi's Treasure Hunt minus Ranger Smith, Snooper and Blabbermouse, Auggie Doggie and Doggie Daddy with Baba Looey included). Yogi (sanguine), Quick Draw McGraw (choleric, albeit a more dim-witted and incompetent example), Snagglepuss (melancholic, although mostly in terms of mannerisms since he's much more upbeat and cheerful than most examples), Huckleberry Hound (phlegmatic), Boo Boo and Baba Looey (leukine), and Top Cat (sanguine/choleric).
The four main kids on Hey Arnold!: Arnold (melancholic), Helga (choleric), Gerald (sanguine), and Phoebe (phlegmatic).
Invader Zim: Zim (choleric), Dib (melancholic), Gaz (phlegmatic), and Gir (sanguine).
The Dark Hand Enforcers (after Tohru left): Hak Foo (choleric), Chow (melancholic), Ratso (phlegmatic), and Finn (sanguine).
The heroes once Tohru joined them: Uncle (choleric), Jackie (melancholic), Tohru (phlegmatic), and Jade (sanguine).
Jungle Cubs: Shere Khan (choleric), Bagheera (melancholic), Baloo (phlegmatic), and Louis (sanguine).
The seven founding members of the Justice League seem to fit this pretty well for the most part: Superman (leukine), Wonder Woman and Green Lantern (choleric), Batman and Hawkgirl (melancholic), Flash (sanguine), and Martian Manhunter (phlegmatic).
Kaijudo: Rise of the Duel Masters has three groups:
The main trio: Ray (choleric/sanguine), Gabe (melancholic), and Allie (sanguine).
The Duel Masters: Nigel (choleric), Nadia (melancholic), Chavez (phlegmatic), Kimora (sanguine), and Jaha (leukine).
The Choten's side: Alakshmi (choleric), Suguru/ Ken Okamoto (melancholic), The Choten (phlegmatic), Fingers (sanguine), and Heller (leukine).
The four members of "Team Possible" in Kim Possible: Kim (choleric), Ron (phlegmatic), Rufus (sanguine), and Wade (melancholic).
King of the Hill: Hank Hill (melancholic), Dale Gribble (choleric), Boomhauer (phlegmatic), and Bill Dauterive (sanguine).
The Hill family also qualifies: Hank (melancholic), Peggy (choleric), Bobby (phlegmatic), and Luanne (sanguine).
Littlest Pet Shop: Zoe and Pepper (choleric), Russell and Sunil (melancholic), Penny and Blythe (phlegmatic), Minka and Vinnie (sanguine).
Men In Black: Jay (sanguine), Kay (melancholic), Elle (phlegmatic), and Zed (choleric).
Metalocalypse: Dethklok: Nathan (melancholic), Pickles (choleric), Skwisgaar (phlegmatic), Murderface (sanguine) and Toki (leukine).
Mr. Bogus: In one of the rare cases that Bogus and his cousin Brattus get paired up with their enemies, Ratty and Mole, it goes like this: Bogus (melancholic), Brattus (sanguine) Ratty (choleric), and Mole (phlegmatic).
For the three main faculty: Miss Finster (choleric), Principal Prickly (melancholic), and Miss Grotke (sanguine).
Regular Show: Benson (choleric), Skips and Pops (melancholic), Muscle Man and Rigby (sanguine), High Five Ghost and Mordecai (phlegmatic).
Rocket Power: Otto (choleric), Reggie (melancholic), Twister (sanguine), and Sam/Squid (phlegmatic).
Rocko's Modern Life: Heffer (choleric), Filburt (phlegmatic), Rocko (melancholic), and Spunky (sanguine).
The human characters of Scooby-Doo! Mystery Incorporated appropriately match their own color schemes. Daphne (Red Hair) is sanguine, the most optimistic and outgoing of the group. Velma (Yellow Sweater) is choleric, exhibiting leadership when solving the mystery, and is rather pushy, and a rather violent Tsundere at her worst. Fred is melancholic as he is the leader of the team, obsessive (when it comes to traps) and emotionally high strung (when Daphne is in danger). He wears... white, rather than black, kinda crashing his color coded bit. Shaggy (Green Shirt) is phlegmatic, the Non-Action Guy who runs from anything spooky, is only there to react to the situations. Scooby (Blue Collar) fits into leukine, as he is rather non-confrontational and the heart of the team.
The main villains, as well: Mayor Jones (phlegmatic), Professor Pericles (melancholic), Mr. E (leukine), and Brad & Judy (sanguine).
To quote the Teenage Mutant Ninja Turtles theme song: Leonardo leads (melancholic); Donatello does machines (phlegmatic); Raphael is cool, but rude (choleric); Michaelangelo is a party dude (sanguine).
Or, for ''Teenage Mutant Ninja Turtles (2003) (the same combination), "Leonardo's always in control; The wiseguy is Michelangelo; Donatello, he's the brains of the bunch; Count on Raphael to throw the first punch!"
Teen Titans: Robin (choleric), Beast Boy and Starfire (sanguine), Cyborg (choleric/melancholic), and Raven (melancholic/phlegmatic).
And as in the comics, the Doom Patrol with Mento replacing Niles Caulder as the choleric leader.
Four youngest children: Flip (choleric), Mimi (melancholic), Nancy (phlegmatic), and Scooter (sanguine).
The middle four: Anne (choleric), Alan (sanguine), Tom (melancholic), and Suzie (phlegmatic).
Mr. Charlie and the two oldest: Mr. Charlie (leukine), Henry (choleric/melancholic), and Stanley (sanguine).
The Amazing Spiez: Lee (choleric), Marc (melancholic), Megan (phlegmatic), and Tony (sanguine). Megan and Marc sometimes switch roles.
The Backyardigans: Pretty hard to qualify. Technically, all of them are sanguine, but Pablo is probably the most. As for the others: Tasha (choleric), Uniqua (melancholic, though not depressive, since we're talking about a little kids' show), and Tyrone (phlegmatic). Austin starts out as phlegmatic, then moving on to melancholic; these days, he's starting to become more leukine.
The Boondocks: Robert (choleric), Huey (melancholic), Tom (phlegmatic), Riley (sanguine), and Jazmine (leukine).
The five household appliances from The Brave Little Toaster: Lampy (choleric), Kirby (melancholic), Toaster (phlegmatic), Radio (sanguine), and Blanky (leukine).
The Flintstones: Fred (choleric), Betty (melancholic), Wilma (phlegmatic), and Barney (sanguine).
The Jetsons: George (sanguine), Jane (melancholic), Elroy (phlegmatic), and Judy (choleric) and Rosie (leukine).
The Land Before Time series: Littlefoot (melancholic), Cera (choleric), Petrie (sanguine), Ducky (phlegmatic), and Spike (leukine).
The Perils of Penelope Pitstop: Penelope is melancholic; Clyde is choleric; Dum-Dum and Pockets are phlegmatic; and the Hooded Claw (Sylvester Sneekly) is sanguine. Of the other characters: Softy (melancholic), Yak-Yak (sanguine), Snoozy (phlegmatic), and Zippy (leukine).
The Princess and the Frog must have read this trope before it was written. Tiana (choleric), Louis (melancholic), Ray (phlegmatic), and Naveen (sanguine).
Transformers has the Dinobots. Grimlock would be choleric when compared to almost any other Autobot, but amongst his own team he's relegated to leukine, with violent, sociopathic Slag as the resident choleric. The other three are fairly cut-and-dried, with pessimist Snarl as the melancholic, quiet and somewhat dim Sludge as the phlegmatic, and affable Swoop as the sanguine.
The five main Autobots of Transformers Animated: Optimus Prime (choleric), Ratchet (melancholic), Prowl (phlegmatic), Bumblebee (sanguine), and Bulkhead (leukine).
Most of the main characters of VeggieTales fit this mold; Bob the Tomato (choleric), Larry the Cucumber (sanguine), Junior Asparagus (leukine), Archibald Asparagus (melancholic), Jimmy Gourd (sanguine/choleric), and Jerry Gourd (phlegmatic).
Wander over Yonder: Wander (sanguine/phlegmatic), Sylvia (sanguine/choleric), Lord Hater (choleric), Peepers (melancholic).