Happy Tree Friends/The Simpsons

Cuddles as Hans Moleman (both are yellow get hurt easily)

Giggles as Lisa Simpson

Toothy as Bart Simpson

Lumpy as Homer Simpson (both are stupid)

Petunia as Marge Simpson (both clean up)

Nutty as Milhouse Van Houten

Sniffles as Professor Frink (both are inventive and wear glasses)

Flaky as Martin Prince

Handy as Scratchy (both's names end in Y)

The Mole as Grampa Simpson

Splendid as Duffman

Disco Bear as Disco Stu (both like to dance to disco music and their names both begin with Disco)

Russell as The Sea Captain (both are pirates)

Mime as Krusty The Clown (both are clowns)

Lifty as Patty Bouvier

Shifty as Selma Bouvier (both's names begin with S)

Cro-marmot as Jasper Beardley (both are frozen in a block of ice (however Jasper was only frozen in a block of ice once and Cro-marmot is frozen in a block of ice forever))

Pop as Chief Wiggum

Cub as Maggie Simpson

Lammy as Ralph Wiggum

Mr. Pickles as Santa's Little Helper