Opening credits monster parts
These are various monster body parts seen in the opening credits that collect letters to form the title. One of them appears to be a large, green serpentine monster who chases down a fugitive "E" before capturing it to complete the title, and then slapping it with its tail to change its font.
Flint's supervisors are a trio of monsters composing of Lenny, a yellow, three-eyed monster with a horn on the top of his head and two eyebrows due to his Picasso-like face, a green, four-armed monster with an eye on a stalk and a pink, four-armed, toad-like monster.
Tiny monster couple
A tiny monster couple living underneath Mike and Sulley's apartment composing of a light green winged monster husband and a pinkish-red monster wife. As the husband flies off to work, the wife tells him, "Have a good day, sweetie!"
Tongue jump-roping monster kids
A trio of monster kids who are playing jump rope with one's tongue in front of the eyeball's house. The kids are a green "Picasso-face", a blue Nancy Kim-lookalike, and an orange Ricky Plesuski-lookalike (whose tongue is used as the rope).
A giant eyeball who looks out a window overlooking the above jump-roping monster kids, who ends up being hit in the eye by one of said kids after he is accidentally flung into their window, causing him to get angry and yell at them.
Garbage collector monster
A giant green monster who sweeps up garbage on the sidewalk and eats them once he's done.
Firebreathing nose-horn monster
A red monster with spikes on his back and a horn on his nose who accidentally sneezes on the newspaper he's reading, causing it to burn up, much to his dismay.
A purple gelatin monster wearing a fedora who accidentally gets his body sucked into a grate after treading on it, leaving only his hat, eyes, and mouth intact, again much to his dismay.
Other Monsters, Inc. employees
These are just generic monsters who work at the Monsters, Inc. factory. It is unknown if any of them are scarers, or at least to Scare Floor F.
These are monsters who are scarer assistants to the scarers. They often tend to wear blue hard hats on their heads.
List of assistants in Scare Floor F:
- Michael Wazowski, who assists James P. Sullivan.
- Jeffrey Fungus who assists Randall Boggs.
- Charlie Proctor, who assists George Sanderson.
- Waxford, who assists Augustus Jones.
- Frank, a one-eyed, four-armed green monster with no visible mouth that has a ruff of fur around his stalk, who assists Bob Peterson.
- Marge, a small, pink, starfish-like monster with two tentacles as its only limbs, who assists Nicholas Schmidt. In the game based off of the movie, she is named "Muscle".
- Betty, a light blue monster similar to Fungus but with two eyes instead of three, who assists Seymour Q. Rivera.
- Kevin, A yellow slug-like monster with five eyes that resembles Chalooby, who assists Theodore Pauley.
- Trevor, A turquoise monster with light blue crab legs and a stalk with one eye as its body that resembles Nancy Kim, who assists Harley Gerson.
- Chuck, a pinkish-beige toad-like monster with four arms who assists Peter Ward.
- Zack, A light green Picasso-face monster with hair similar to Smitty's who assists Ricky Plesuski.
- Sylvester, A red slug-like monster with five eyes who assists Bud Luckey.
- Vince, A light green, slender monster with around four or five legs that assists Joe J. Ranft.
A pink six-armed toad-like monster who has a sapient tongue resembling a light blue slug who eats his food for him.
These are monsters who are seen as customers at Harryhausen's sushi restaurant. Some of the customers include a purple Rivera-lookalike, a green Nancy Kim-lookalike, a gray Charlie-lookalike, a green Claws Ward-lookalike, and a female pink monster with Rhonda Boyd's head and Ms. Nesbit's body.
News anchor monster
A yellow monster resembling Lanky Schmidt who serves as the news anchor on various TV monitors.
Ms. Nesbit's students
These young monsters are Ms. Nesbit's students the teacher brought to the factory as part of a field trip. They include Baby Smitty, a green "Picasso-face", a light green Bile-lookalike, and an orange Charlie-lookalike.
Students at Monsters University
Little is known about these monsters aside from the fact that they are all students attending Monsters University.
The monster students that do not belong to fraternities Jaws Theta Chi (JOX), Roar Omega Roar (ROR), and/or Oozma Kappa (OK) would probably belong to either Omega Howl (OH), Gamma Roar Roar (GRR), and/or Slugma Oozma Python (EOP); while those who do not belong to sororities Slugma Slugma Kappa (EEK), Eta Hiss Hiss (HSS), and/or Python Nu Kappa (PNK) either belong to Slugma Kappa Theta (EKO), Chi Phi Argma (XOA), and/or Argma Slugma Argma (AEA).
Some of the students include:
- Snuk McGert (a light green Lanky Schmidt-lookalike with prominent buck teeth)
- Kendra Mosch (a light yellow monster with a single eyestalk on her head and two upward-pointing horns on either side)
- Lars Bvellum (a light blue monster with green bat wing-like eyes, two slug-like eyestalks, and a fanged mouth)
- Bart Gates (a quarterback)
- Uriah Pemberslime (a fullback)
- Harry Phiegel (wide receiver)
- Timbo "The Motor" McGee (a swimmer said to have a worm-like body and seven legs)
- Zane "Great Wall" Xiao (a ping-pong champion)
- Jennifer/Jessica Macklin
- Phyllis Longslime
- Turner Dourton: See here.
- "Eyestalk" Football player
- Giant Slug Football player
- Tommy Flaggerton
- Langer Bracht
- Salma Burien
- Van Earl Jr.
- Turck Gleason
- Horace McStomp
- Blast Phillips
- Purple Eyestalk Monster: A purple eyestalk monster wearing one-lensed glasses who attends the astronomy club.
- Tic-Tac-Toe Monster: See here.
- Male Purple Nose-horned monster: A hairy purple monster with a horn on his nose and two more on either side of his head wearing a Monsters University jacket.
- Female Purple Nose-horned monster: A female version of the above.
- Andy Fungus: A light green slug-like monster. Despite having the surname Fungus, he is completely unrelated to Fungus, Randall's scare assistant.
- Green Striped Brynn Larson: A female green monster resembling Brynn Larson with dark green stripes down her back with fin-shaped pigtails.
- Female Blue Waxford
- Maggie Stillwater
- Nose-Horned George Sanderson: An orange George Sanderson-like monster with a horn on his nose instead of on his forehead.
- Omega Howl Student: An obese purple monster with a horn on his nose and shaggy orange hair who appears to be the only student of his fraternity seen in the film.
- Salmon Carla Delgado: A salmon pink female octopus-like monster resembling Carla Delgado with orange spots on her body and fin-like ears.
- Green Maria Garcia: A green furry slug-like monster resembling Maria Garcia with red hair covering one of her eyes.
- Giant Female Frisbee Monster
- Blue Marge DJ
- Blue Waxford Drummer
Monsters University Faculty
- Dean Hardscrabble: See here.
- Professor Knight: See here.
- Dr. Tawny Van der Slime: See here.
- Dr. Rufus Oozeman: an obese yellow-green monster with a black nose and dark green fin-like hair.
- Dr. Timofus Trimboleek: a light brown monster with one eye and two ram-like horns.
- Dr. Philo Carter: a female blue Lanky Schmidt-lookalike with purple eye shadow and long eyelashes.
- Dr. Seecrus Janus: a rectangular yellow monster with two upward-pointing fangs protruding from his lower jaw and three eyes and wears three-lensed glasses (similar to Fungus).
- Timothy Rastrussen: a furry light green monster with three horns on his head.
- Victoria Gross
- Librarian: See here.
- Janitor: A furry purple monster with a horn on his nose and a thick mustache serving as the school's janitor who appears at the end of the film where he notices the Slug Monster arriving in "his first class" only to tell him that the school year is now over and that he has missed every single class he's supposed to attend, causing Slug to slither back out.
These are monsters who act as security guards to Monsters, Inc. They chase down Oozma Kappa one night when they sneak into the factory grounds (Art was once said to have been sent to jail for an unknown crime), only for them to all escape in Ms. Squibbles' minivan. Several different security guards arrive during the climax along with the CDA when Mike Wazowski is unexpectedly trapped in the human world and Sulley trying to save him where they are distracted by the rest of Oozma Kappa when Dean Hardscrabble depowers the door only for Mike and Sulley to repower it by scaring some adult police officers while in the human world.