Someone else for me thank you.
My top pick at the moment would have been Loki, for an evil villian, to a good, funny, manipulative Kid Loki. I find his character the most interesting.
Others I like would be Rogue , or Magneto . Not sure if Genis Vell counts? He went to Asgard and shot Hemidall just for lolz in volume 4.
Thanos at one time was a reformed bad guy turned good, before marvel said heck with this, we like Thanos as a villain better.
There is also Moonstone, who currently is a good guy/ girl, always found that character fascinating.
It's between Morbius and The Shade for me. Both have been handled very well in recent years.
Deadshot. Pied Piper. Trickster.
Idk if I'd give Deadshot the same credit as the others. He certainly walks a much more fine line than the Piper. He's usually just doing whatever he does for the cash (so he says). However, I do consider him a personal hero just for offing The Fiddler. :D