I apologize if a thread like this has been done already.
Bloodsport (Alex Trent). Given the resurgence in people being openly white supremacist in the U.S., it only seems appropriate.
Kryptonite Man -- the version created by Kurt Busiek in Superman #650 (2006).
Baron Sunday -- I'm sure something creative can be done with him.
Kyber -- another Kurt Busiek creation. I thought he had potential.
Subjekt-17 -- see above.
Mr. Z -- has he even been seen since the early 1990s?
Thaddeus Killgrave -- a John Byrne "mad scientist" creation that nobody has ever done much with. He might be fun in the right hands.
Any others y'all like?