It's probably been 40 years since I read superhero comic books, but as a kid I bought each new Batman and Superman comic -for 15 cents each. Still, I don't recall some of the more obscure villains that plagued the Caped Crusader. Comic book readers would probably like to see more variety in the movies, so Gamma Squad has some suggestions. Shown here is Flamingo, which is a more recent villain.
Flamingo is basically Prince as a psychotic, lobotomized mob killer. Grant Morrison's Batman run had it's ups and downs, but Flamingo was a definite giant, pink up. This guy not making the Arkham Origins assassins list while not even remotely assassin-like Killer Croc did is a true injustice.
Oddly, Flamingo is number ten on this list of nine. Go figure.