You Big Eared Freerf
This much-maligned Legend of Zelda game for the Philips CD-I brought us classic YTP lines like "My Boy", "Squadalaa, We're Off", and "Come Back When You're a Little, Mmmm, Richer!"
What is Link: The Faces of Evil?
This food item is a reocurring gag across multiple famous YTPs, most notably featured in the "Fesh Pince of Blair" trilogy when Carlton requests it to be made multiple times.
What is a sandwich?
In the Misadventure of Skooks' infamous "Where's the Caveman" bit, Shaggy clarifies the location of himself, Fred, and the Caveman (who's also the Sheriff) this many times.
What is six times?
(Shaggy clarifies they're out here, the caveman is in there, that they're frozen out here, then they're in there, then they're out here, then that he doesn't know where the caveman is.)
A classic 2009 YTP that would later go on to inspire the KEYGEN joke in Deltarune involves King Harkinian downloading this video editing software.
What is Sony Vegas?
The modern superstar YTP "Good Old P.U." derives its name from this classic Merrie Melodies short that had its own day in the YTP sun with the sound clip "I'll steal it, no one will never know!"
What is The Dover Boys (aka The Dover Boys at Pimento University; or, The Rivals of Roquefort Hall)