Mordecai and Rigby for being the best millennials ever. Helga G. Pataki for being a pretty damn complex but well fleshed out character. Tom and Jerry for being the masters of slapstick humour. The Loony Tunes cast for bringing me endless joy in their various incarnation. DC heroes (Batman, Static Shock, Teen Titans, etc.)... I can't stand any of the live action DC movies but animated DC stuff is on point.
Honorable mention goes to Scooby and Shaggy from Scooby-Doo and Babar.
Finn the Human. This boy straight up kicks ass, from psychotic horror demons to monsters created by nuclear radiation. He loses his arm trying to stop several inter dimensional criminals (including his deadbeat dad). He (for most of the series) is presumed to be the last human on what's left of Earth. A true G