Avengers 4: 9 Surprise Cameos That Could Still Happen

2. One Of The Fox Properties

Though it might be a case of 'too little, too late' for the inclusion of Marvel's Fox properties in Avengers 4 - with the Disney merger still under review - the film is scheduled for reshoots this autumn, meaning that the door's still open for such a thing to happen.

Ignoring for a second all the logistics, complications and behind-the-scenes wrangling it'd take to get either one of the X-Men or Fantastic Four to make an appearance in the film, it's clearly a thing fans want to see happen in the coming years, but if Marvel can bring Reed, Sue, Johnny and Ben to the big-screen next year, it would make for a surprise unlike any other.

Of course the X-Men present the more bankable opportunity, but there's no denying that the Fantastic Four - the franchise that, along with Watchmen, launched Pixar's own Incredibles series - is tailor-made for Disney's MCU. The group have the potential to go toe-to-toe with the Avengers, and with talk of the MCU's next phase being its most unique yet, introducing the Four now - or even the X-Men - makes plenty of sense.