1. Booster Gold
It has to happen. It just has to. Booster has one of the most feverishly loyal cult fanbases of any comic book character out there. Theres no shortage of people roaming the mall in a Batman or Superman logo t-shirt, but the fans of Booster Gold operate on a whole other level. Out of all the entries on this list Booster is the one that I would be most shocked if Injustice didnt eventually include. The drawback is that using Booster Gold might lighten the mood and atmosphere of Injustice, but honestly with all the doom and gloom would that be such a bad thing? Now they could go the dark and gritty root and focus on the later depictions of Booster trying to undo some of his sillier antics, but what fun would that be? I say bring in the comic relief, lighten the mood a little bit. Just DO NOT make him this games Johnny Cage.