Cartoon Characters who became Human:

Characters who temporarily became human:

At the end of the 2004 SpongeBob Movie, King Neptune briefly turned Mr.Krabs into a real boy

This is how Brian Griffin Looks like in the alternate universe where Dogs are people and people are dogs.

In the 1978 TMNT Series Michael Angelo turned into a human after eating anti mutagen cookies baked by shredder, His brothers helped him turn back into a Turtle.

Jenny XJ9 has an exo-skin Human suit she uses for disguises

In Transformers Animated the Autobots thought they turned into humans, but it turned out Soundwave was hypnotizing them in a simulation.

In season 3 of G1, the Autobots also turn human But this time its Rodimus, Ultra Magnus, Arcee, and Springer

The Watersons temporarily become human during the episode the Nuisance where they become model citizens.

In an issue of Sonic the Comic, Sonic had a Dream that he was a human, and tails was also apart of the dream, yikes. The smell of a rotting egg that he was about to eat woke him up.

And last but not least Outside of Pinocchio Human Shrek from Shrek 2 is probably the most famous of this trope.