9. Black Flash
Along with Reverse-Flash (more on him a little later), The Black Flash would serve as an interesting parallel to Barry Allen in the CW series. As you may already know, he essentially fulfills the same role as “Death” for those who possess super-speed in the DC Universe, returning them to the source of their powers: the Speed Force. While that’s really about as far as his role in the comic books goes, there’s room for a few elements of The Black Flash to be tweaked in a live-action adaptation. He could perhaps haunt Barry throughout the season, resulting in a battle between the two or could be used as some sort of shadowy nemesis with a further developed reason for wanting to take anyone connected to the Speed Force. Arrow has done a great job of fleshing out and reimagining characters like this, so there’s no doubt that the same could be done in The Flash!