Also doubling as a Brick Joke: in one episode, Garfield & Nermal contend with mutant guppies, who they defeat by chasing them back into the sewer. Said guppies then appear in the subsequent US Acres Quickie; after scaring Wade and Orson, one guppy turns to his fellows and says "Come on guys, let's go see if we can get a guest shot on the Muppet Babies, whaddaya say?" (Muppet Babies aired opposite the show on CBS at the time).
Aloysius Pig is Kevin Meaney in a pig costume. They both even share two catchphrases! note "That's not right!" and "I don't care!", even though the latter was only said once
In "Clash Of The Titans", as the gang is flying home, Garfield asks if the characters can stop at Teenage Mutant Ninja Turtles so they can get a pizza.
In "Temp Trouble", we have this line: "Mrs. Pig, it's Saturday morning. Do you know where your children are?". Ironically, the thing the quote shouts out to note A message broadcast on TV at 10:00PM was based off Wee Willy Winkie, a nursery rhyme that would be spoofed 8 episodes later.
In "Kiddie Korner", Aloysius says that sitting on a tuffet "sounds naughty". This could be a reference to a Dot's Poetry Corner segment of Animaniacs that aired a year before this episode, where Dot reads Little Mrs. Muffet and uses "tuffet" as a euphemism for "butt", while showing us her panties doing so.
How about "A Shout-Out to Itself"? One US Acres quickie had Roy on a stage in a competition involving baaing and cocking against Lanolin. One season later, the same stage reappears in the Laryngitis quickie, and he stands on it in almost the exact same manner!