7) The Inhumans
The original plan for Phase Three of the MCU would have seen it rounded off with The Inhumans, a movie about a race of enhanced humans who many were theorising would be Marvel’s answer to the X-Men.
J. Robert Cole was writing the screenplay and it was pencilled in for a November 2nd, 2018 release date, before being moved back to July 12th, 2019. In advance of the movie, the Agents of S.H.I.E.L.D. TV show introduced the concept of Inhumans.
In April 2016, however, Marvel announced that Cole’s work had been discarded and Inhumans was removed from the release schedule. As of September, though, it’s still not officially cancelled and it’s thought that it will eventually re-emerge from development hell in the near future.