This is a list of characters who are worth mentioning, but not not significant enough to warrant their own page.
Main TV Series
| Image | Name | Voice | Description |
|---|---|---|---|
 |
Jimmy (birthday boy) | Jeff Bennett | Jimmy was the the kid whose birthday party it was in "Just Set Up the Chairs". He was shown to be quite rude and unlikable, sitting alone on the bus and yelling at Benson for wishing him a happy birthday. |
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Special Entertainment | Mark Hamill (clown)
Jeff Bennett (pony) |
The Special Entertainment consists of an anthropomorphic pony and an intoxicated clown. They were hired to entertain the kids at Jimmy's birthday party. Shortly after, they were killed by the Destroyer of Worlds. |
 |
Slasher | S. Scott Bullock | Slasher was Margaret's boyfriend at the time of "Caffeinated Concert Tickets". They broke up after he insulted Mordecai for his lack of strength. |
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Cheezer's Cashier | Janie Haddad ("Grilled Cheese Deluxe") Chelsea Kane ("Gymblonski") |
She was a cashier at Cheezer's. She was shown to be gullible, believing that Mordecai and Rigby were astronauts. She was still working at Cheezer's by "Gymblonski", when she is working during the Food Run. |
 |
Dr. Asinovskovich | BJ Ward | A scientist at the Compound. Mordecai lied about her loaning him a pink sweater at a conference, which she gets embarrassed about due to her having memory of the fictional event. |
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Jimmy (scientist) | James Sie | Another scientist at the Compound. He had trouble working with Anti-Matter, but was ignored by the Astronauts when he tried to make this issue known. |
| Angel | Sean Szeles | Angel was one of the singers at the Coffee Shop's Open Mic Night in "Mordecai and the Rigbys". He was in a relationship with Margaret, but they broke up eventually off-screen. |
Season 2
- Matt: He worked at the Movie Shack Hut as an advertiser by wearing costumes. He dressed up as a British Taxi from the movie Ello Gov'nor but Rigby thought he was the real thing and tried to beat him up.
- Hooligan: In Rigby's dream in Ello Gov'nor, he tries to kill Rigby, but Rigby is about to beat him up, but the British Taxi comes along.
- Dizzy Zombies: A bunch of monsters who are the same as Iacedrom and Ygbir.
- Jimmy (Taco'Clock Worker): A worker at Taco'Clock, he thinks Mordecai & Rigby are losers.
- Bobby: A friend of Muscle Man, who loves his jokes. He works at the Nursery and appears in My Mom, See You There, TGI Tuesday and Dumped at the Altar.
- Jack Farley: A business man who thinks Mordecai and Rigby are awesome.
- Young Gamers: A couple of young children who knocked Mordecai and Rigby over with their skateboards.
- Centaurs: A few centaurs who went to Mordecai and Rigby's party.
- Guest on Fire: A guy who seems to know Mordecai and Rigby. And their toilet.
- VG: The old Movie Hut Shack worker who got sucked into a movie called Planet Chasers: Starlight Excellent, he was most likely fired.
- Leon: The old park manager who quit his job and became a slacker. His friends call him Upe, short for Utopia.
- Jinx Demons: What you turn into if you get scratched by Negative Rigby.
- Howard Fightington: A zombie who was seen in Grave Sights.
- Museum Guards: Guards of the future Night Owl museum.
- Teacher: A maths teacher at a local college, who kicked Rigby out of school in More Smarter and passed Eileen in Video 101.
- Rochambeau Monster: A monster who tried to destroy the park after suck up everything after Mordecai and Rigby tie 100 times in Rock, Paper, Scissors.
- Wedgie Ninja: A ninja who gives people wedgies.
- Road Hog: A driving pig who crashes a car.
- Old Man Horseshoes: An old man who has horseshoes for hands and gets struck by lightning.
- Carl: A bouncer who tries to get rid of Mordecai and Rigby.
Season 3
- Dave: Benson's old apprentice for Stick Hockey. He got his head chopped off.
- Park Ranger: A character who doesn't like people using restricted areas.
- Das Coolest Employee: An employee at a clothes store who thinks Mordecai and Rigby are cool for giving him a load of money.
- Margaret's Boss: The boss of the coffee shop.
- Big Trouble: A rival rapper of CrewCrew.
- Chad Ironchest: A man who pretended to be Margaret's boyfriend so Mordecai would get jealous.
- Tuck Packard: A man who pretended to be Eileen's boyfriend so Rigby would get jealous.
TBA