Esmeralda (Hunchback of Notre Dame)
Spaceman Spiff (Calvin and Hobbes)
Rockabilly Two-Face (I guess?)
Justine McKenny as Chelsea Checkers (My Gal, the Zombie). Not really cosplay, since Justine portrays Chelsea professionally on TV!
Recent pages I added to the DC Comics Database:
Julius Caesar (New Earth)
Kublai (New Earth)