#4 AJ Styles

When AJ Styles was drafted to SmackDown Live in 2016, it wouldn't take long until the Phenomenal One would hold the WWE Championship.
And whilst his second reign was far more impressive than his first, more memorable fans will remember that this first reign came to a quick end, at the hands of Cena.
Although both Cena and Styles are huge stars on the blue brand, neither are with a WrestleMania opponent, making a match between the two all the more likely.
If so, there's no shortage of stories that the WWE could take, especially if they turned the Phenomenal One heel.
If not, then the story could be as simple as both wanting to prove just how good they are, as fans would remain glued to their screens as they see the two icons face off again.