4. Catwoman
Catwoman has been prowling the streets of Gotham City for over 70 years, and has and quite the colorful history with the caped crusader. She's ranked #11 on IGN's list of Top 100 Comic Book Villains of All Time list, and is interestingly #20 on their list of Top 100 heroes. She's often played around on both sides of the law, sometimes thwarting Batman at every turn, other times allying with him and other DC heroes. Really, she doesn't belong on either side, and only swears allegiance to herself; acting accordingly to what will benefit her most. We've seen several variations of Catwoman on screen, most notoriously in her atrocious 2004 solo film, and most recently in 2012's The Dark Knight Rises. She's had small parts in animated films, and has shown over her long comics history that she's interesting and intriguing enough to hold our attention. As far as a story for which to tell in her own animated film? I recommend Jeph Loeb's When In Rome. Catwoman: When In Rome is a six part miniseries written by Loeb and drawn by Tim Sale. It features Catwoman, on a trip to Rome with The Riddler in search of the identity of her father (whom she believes to be crime lord Carmine Falcone). It's a companion piece of Loeb and Sale's Batman: Dark Victory and takes place during the latter parts of that story. Needless to say, she makes some enemies and gets into trouble along the way. It's a good story with a few twists and turns we've come to expect from Loeb, and would make for a great animated film.