9. The Incredible Hulk 2
Ever since the Marvel Cinematic Universe successfully reintroduced The Hulk as played by Mark Ruffalo, fans have been wondering when Marvel Studios will get around to making a standalone follow-up to 2008's The Incredible Hulk.
In fact, the project's never been officially confirmed in any capacity, with Kevin Feige frequently acting coy about rubber-stamping another Hulk solo film.
It was finally revealed in 2015 that the main obstacle is Universal holding the distribution rights to the character's standalone films. By having the big green guy appear as a supporting character in movies such as The Avengers and Thor: Ragnarok, Marvel Studios can avoid all the legal red tape.
Even with the underwhelming box office history of both prior Hulk blockbusters, there's no doubt a new solo Hulk movie would do gangbusters business.
However, with Universal's hold over the character having no end in sight - as it's most likely renewed every time he appears in a new MCU film - it's probably never happening.