9. The Infinity Gauntlet
The fact that Marvel has already announced plans for the two-part Avengers: Infinity War (along with a teaser featuring Josh Brolin's Thanos wielding the Infinity Gauntlet) means that this story being adapted is obvious, but it's not clear what from the comic books it's going to borrow or how will Avengers: Age of Ultron help to set the stage for Thanos' arrival. Well, it's believed that Tony Stark will experience some sort of vision of the Mad Titan thanks to the Scarlet Witch, so he will obviously have some sort of presence here. The movie's mid-credits scene has also remained a closely guarded secret up until this point, so he could cameo there too, especially if the rumours of Thanos being in Thor: Ragnarok are true.