It seems like everybody's switching sides these days. In the Marvel Universe, a group of Avengers have gone underground to form an illegal resistance to the Meta-Human Registration Act, and a group of villains have formed a legal group, the Thunderbolts, that hunts down the metahumans who resist the Act. Over at DC, there are side-switchers galore. Mary Marvel's evil, the Riddler is solving crimes and the Trickster and the Pied Piper can't figure out what they are.
It's getting so a guy needs a scorecard to keep up with it all.
So that's what I did. Send your suggestions for further Side-Switchers to me at Bguigar (at) yahoo (dot) com.