A Power Girl Super girl team up. A Black Canery one would be great as well. She-Hulk (with fourth wall breakage would be cool (it is part of her character, at least it was)). Captin marvel the second incarnation of the character, Monica Rambeau. It would be a very radical superhero movie. I mean a black female lead. Just imagine the outrage the would cause. Aurora would be cool to see but they would have to include Northstar. Hey a female main character and a gay main character. I don't think Hollywood could ever be ready for that. Wanda Langkowski would be an interesting one to see. Though not very likely. I mean it is pretty confusing in the comics are werid sort of way how Wanda Langkowski became Wanda Langkowski when she was originally a man. (Wiki it. Its a confused and messed up story).
Jill Carlyle, the Crimson Avenger. Shes like a mystical Punisher. She used a pair of guns to kill for revenge but the guns were cursed that whoever used them for revenge was forced to hunt those who prayed on the innocent forever. Spider-woman a.k.a Jessica Drew. Though I'm not sure if she is Marvel or Sony owned right now. I mean her powers are different from Spider man and beyond the name she doesn't really have much of a connection with him. Bah likely messed are a pain.
You know its very hard to find female characters that are not part of a team or an offshoot of another bigger hero. I mean a lot of female superheros in Marvel are mutants (or at least some of the better known ones are) or come from another part of team like the Fantistic Four for example (Crystal, Sue Storm, She-thing (its a thing, look it up) etc. Oh that reminds of another one. The Wasp. Hey if they are doing an Ant-Man movie they can do a Wasp movie. I mean she was a charter member of the Avengers (and most likely is best known from that team). For DC beyond Wonder Woman the only female leads I can think of are: Birds of Prey, Batgirl, Batwoman, and Supergirl. Though Stormwatch has a couple of strong female main characters but they aren't really all that great.