I know I'm getting into to this thread late but heres a few:

Widowhead (Because he has such a "wido head" not!)
Fizzgig (because I like that name and he looks like trouble)
Tracer (because he looks like he can move like a shot)
Clip (because he looks like he wants to move at a fast clip)
Thanatos (because he looks like he wants ta kill ya, he's even licking his chops!)