Concept artist Stephan Martiniere put a treasure trove of Suicide Squad concept art up on his website, and what it mostly revealed is that Enchantress and her henchman could have been a lot more interesting than the designs we actually ended up seeing in the movie.
While Martiniere does have one design for Katana up there, the vast majority of the art is different forms for Enchantress, her brother and her disgusting mooks, and they’re much more otherworldly.