venom- because of the way he appeears and he is super powerful, sabertooth- because of his abilities and powers, rhino- because of his lack of witts and apperance, lizard- because of his apperance and powers, and iron maunger (sorry if i spelled long)- because of his giant-sized apperance.
Loki, but not just because of his looks. His character really tugs on your hart-, hart string and he goes about his nasty villainous things with the sense that what he's doing is right and fair. His back story is interesting and emotional and u really feel like u understand and can (in a weird kind of way) relate to his actions as a villain.
But also who can resist his cheek, humor and that smile.