5. Nuke

Although this villain became a memorable character in the Daredevil comic books, his origins were explored in the Captain America ones "“ of course, we don't expect to see him as upgraded as he is in the comics, just like we're pretty sure that his pills won't be as colored "“ however, he is one of the villains that could stand a chance against Captain America. Of course, he won't work as a main antagonist "“ however, it is expected that Civil War will have quite a few villains. So why this psychotic and cybernetically enhanced antagonist wouldn't be present?

4. The Secret Empire

As said, and while we know that two factions of heroes will clash, Civil War will have its fair share of traditional villains. And since HYDRA played an important part in the shaping of Captain America and the triggering of the MCU's Civil War, maybe a faction of it should be present in the movie adaptation.

Of course, this is a group of villains with which the minds behind Marvel could play a bit "“ after all, AIM ended up pretty well in Iron Man 3, even if the comic book sources weren't respected.