The Marvel multiverse is vast. There are hundreds of characters and stories that would be great on the big screen. What would you like to see?
My pick is Agents of Atlas:
Founded as the G-Men in 1958 by FBI agent Jimmy Woo to rescue the President from Yellow Claw, the team recently reformed in recent years as the Agents of Atlas after Jimmy took control of the Atlas Foundation after the death of it's leader, Yellow Claw. The original line up of Jimmy Woo, Venus, Namora, The Uranian, Gorilla-Man, and M-11 has expanded to include Mr. Lao, Temugin, Derek Khanata and 3-D Man. The team has a reputation for shadiness and operating under the radar.
An ideal Agents of Atlas film would run like a cross between Guardians of the Galaxy and The Winter Soldier.
I really want a well done Venom/Carnage/Spider-Man movie. Venom is one of my favorite characters and having something like this would be incredible. The story could also link well with other parts of the MCU, since currently Venom is serving as a Guardian of the Galaxy, which would be interesting to see.
The Skrull invasion would also be really cool to see, but sadly it most likely will never happen since Fox has the rights to it along with the Fantastic Four.