7. Matthew Keller - White Collar
I spent a lot of time debating if I should include Matthew Keller on this list or not but as you can se he has made the cut. Neal Caffrey himself is incredibly clever and witty and on the show no one is usually able to match wits with him. Except for Matthew Keller. Keller, played by Ross McCall, is the only worthy antagonist to the infamous Caffrey. Even tricking Neal into going to the very edge of his tracking anklet radius, almost putting him outside of it. There hasn't been much of Keller since the last season and I honestly hope he returns soon.