Ideas for more Dark Knights:
Black Bruce/Gold Bat/BatGod (Batman + Black Adam) - Bruce Wayne travels across the world and meets the Wizard and gives Bruce the power but Bruce comes back to Gotham and rules it like a god.
The Batman/King Bat/Kryptonite Bat - Lex Luthor as Batman
Hawk Bat (Hawkman + Batman) - Bruce is an reincarnated Egyptian prince