#1. John Cena's return to WWE
A huge reason why John Cena is the top entry on this list pertains to how WWE will bring him back in the first place. Cena appeared in a trippy and surreal Firefly Fun House Match against Bray Wyatt at WrestleMania 36.
The leader of the Cenation fell victim to Wyatt's mind games as the 16-time world champion faced his deepest fears. "The Fiend" Bray Wyatt defeated John Cena at The Showcase of the Immortals, and Cena hasn't appeared on WWE programming since.
The Fiend tends to change the course of his opponent's career. So, it's a safe bet that John Cena may not be the Superman caricature he once was when he returns to WWE.
Lately, the 16-time world champion has been busy working on various film projects in Hollywood. Incidentally, Cena also revealed an all-new look complete with a goatee.
John Cena has plenty left in the tank to deliver a few more WWE matches, so a return to the company seems inevitable. Until then, WWE fans will keep speculating about a potential heel turn for Cena, which could be an interesting follow-up to his encounter with The Fiend.
If they both finally turn heel, a rematch between John Cena and Roman Reigns could also be one of the most intriguing matchups of WWE's current era.