The Pigs in Space clip you refer to is from the short lived Muppet Babies and Monsters hour, also using a clip of Kermit PI.
There were numerous clips used from 3 Stooges shorts (aptly fitting, as I've mentioned Jefferey Scott was Moe's grandson).
Then of course, there was the random public domain clips they used. In the episode where they ordered a play house from a cereal box, and dream of what it's like, Fozzie dreams he's a Mickey Mouse club parody. During which time they show a black and white cartoon, which used clips from the old "Popeye meets Ali Baba's fourty theives" cartoon, the clock pulling it's numbers with its hands and hides, the painting of a man in a turban flipping himself over to face the wall, and (I think) a coat rack running away and a guy in a turban jumping into a flower pot were used.
In the Daily Muppet a short clip of Oscar the Grouch was used.
I also recall clips of "hey Verne, It's Ernest" being used in one episode, but I'm really fuzzy on that one.
I know Spiderman was animated into an episode (and Stan Lee made a live action appearance) but that's probably because Marvel was the production company!
There were numerous clips used from 3 Stooges shorts (aptly fitting, as I've mentioned Jefferey Scott was Moe's grandson).
Then of course, there was the random public domain clips they used. In the episode where they ordered a play house from a cereal box, and dream of what it's like, Fozzie dreams he's a Mickey Mouse club parody. During which time they show a black and white cartoon, which used clips from the old "Popeye meets Ali Baba's fourty theives" cartoon, the clock pulling it's numbers with its hands and hides, the painting of a man in a turban flipping himself over to face the wall, and (I think) a coat rack running away and a guy in a turban jumping into a flower pot were used.
In the Daily Muppet a short clip of Oscar the Grouch was used.
I also recall clips of "hey Verne, It's Ernest" being used in one episode, but I'm really fuzzy on that one.
I know Spiderman was animated into an episode (and Stan Lee made a live action appearance) but that's probably because Marvel was the production company!