This is a list of spoofs/references/parodies of Regular Show from other television shows and networks or movies
Cartoon Network is the channel Regular Show airs on. In the middle of some commercials on the network, "Yeeeauhhhh!" will appear on the screen and someone (either C or N) will shout Mordecai and Rigby's basic and most common catchphrase, "Yeeeauhhhh!".
Jeopardy!Jeopardy! has featured Regular Show as an answer for the question A 6-foot tall blue jay named Mordecai and Rigby the raccoon are best buds on this Cartoon Network offering.
Mordecai and Rigby appear in a few episodes of MAD.
In one episode of Jimmy Kimmel, they showed the clip of "Brain Eraser" where Benson's "slot" went up.
The Problem Solverz
In The Problem Solverz episode, "Hamburger Cavez", 2 animals that look like Mordecai and Rigby were seen near the hamburgers Roba and Horace saved, and they were eating them. Rigby lookalike was much like a mis-made Ybgir, and Mordecai lookalike had Horace's eyes, and Iacedrom like body. This was also noticed on Calvin Wong's Tumblr.
Madness: Project Nexus
In the season eight episode "The Missing Kink", it showed a raccoon giving cocaine to a blue jay in the woods.
In the episode "Cat Fingers", Amythest, one of the Crystal Gems takes on the form of a Blue Jay. When Pearl tells her to stop in order to avoid "Overdoing" her abilities, Amythest tells her: "Aw, chill it dude!" in a fashion very similar to that of how Mordecai would say it.
The Amazing World of Gumball
The episode, "The Refund", features a similar plot to the Regular Show episode, But I Have a Receipt.
In the episode, "The Apology", Gumball and Darwin find a dollar on the floor and yell "OOOOOOOOOOOOOOOOH!", which Mordecai and Rigby always say when they're excited.
At the start of Little Dipper, Dipper beats Mabel at chess and shouts a brief "Oh!"