Dogs:
* Snoopy: The iconic beagle from the Peanuts comic strip is arguably the most famous cartoon dog ever.
* Lassie: This Collie from the books and movies is known for her loyalty and intelligence.
* Buddy (Air Bud): This golden retriever from the movie franchise became a symbol of canine athleticism.
Cats:
* Garfield: The orange tabby cat from the comic strip is known for his love of lasagna and sarcastic humor.
* Grumpy Cat: This internet sensation with her perpetually grumpy expression became a meme and a cultural icon.
* Lil Bub: This cat with a rare bone disease became a popular internet celebrity for her unique appearance.
Other Animals:
* Hamm: The pig from the Toy Story franchise became a favorite character for his wit and personality.
* Snowball (Minions): This adorable white bunny is a beloved character from the Despicable Me franchise.
* Mr. Ed: This talking horse from the TV show of the same name became a cultural phenomenon.
Ultimately, the most famous pet is a matter of personal opinion and depends on your definition of "fame."