Source: walldevil.com

4. Annihilation: Conquest

Cosmic Marvel is quite fun.

I mean, we saw how awesome it could be in the Guardians films and Thor: Ragnarok, but it appears that the time has come to make a big space epic. And for that, I'd suggest combining the first and second Marvel Annihilation events.

In Thanos’ wake, the Annihilation Wave heads for Earth, and our already beaten-down heroes have to pull it together to fight against it. They're way out-powered as they are, so they have to bring in additional cosmic-powered heroes, including Captain Marvel, Adam Warlock, and Nova. And once they fight their way through the first groups of aliens, they come face-to-face with the true threat: Ultron, who survived his incredibly brief Age by beaming his last refuges of consciousness into outer space, where they all found a home with the alien machine-people known as the Phalanx.

An old enemy returning in a new way is pretty much the only "pure Marvel comics" thing that we have yet to see in the movies. It would be fun!