Clayface may be the grossest LEGO guy I've ever attempted...here's he's a LEGO construct with lots of Sculpey put on him, baked, and painted. Not my best effort...and yet that's kinda what Clayface looks like. Uh...clay.
Ra's Al Ghul and Talia...he's in need of a cape.
Firefly--a simple custom that turned out pretty sweet.
Mad Hatter. I think I went overboard on his hat.
Black Mask, Harley Quinn (made before the official minifig came out in the second wave of Batman sets), and Man-Bat. I really wish they had produced an official one of him. He's using a Werewolf head, which is biologically inaccurate, but it works well.