13. Prometheus
When I first heard of the Batman villain Hush, I assumed people were just talking about Prometheus. In every respect, he is the anti-Batman. He is brilliant, technologically advanced, and even has a similar back story. Howeover, more than just being decked out with awesome stuff, he's also a serious threat. Just ask Green Arrow. Prometheus would be an interesting villain to appear on screen. Sort of like a man prepared to take down anyone and everything. He'd exploit all of the League's weaknesses with his tech, forcing them to work together. Granted, Prometheus has been beaten before by Batman, but he'd probably best work in a group of villains. More on that later...