Old School Daffy Duck. Not the duck season/ rabbit season one the actual classic one. Him in a boxing match with the rooster was my favorite Looney Tunes episode ever. I laughed so much I couldn't hardly breathe.
Robin from Young Justice, Stan from South Park, Ben from Ben 10, Princess Bubblegum from Adventure Time, Trixie from Fairly Odd Parents, Kuki from Kids Next Door...and I definitely have a ton more, but those are all that come to mind right now.
eric, kenny and stan (south park)
roger and stan (american dad)
bender and fry (futurama)
zim, gir, tak, gaz, dib, skooge, the mighty tallest, the pig guy from the pizza place, tak's ship, zim;s robo parents, and finally, the resisty (invader zim)
brian, peter, peter's fake dad and quagmire (family guy)
and of course, phineus, ferb and perry