4. AJ Styles

Many thought hell would freeze over before AJ Styles laced up his boots in a WWE ring, but truth can be stranger than fiction.
Despite so many things that normally prevent a wrestler from having a WWE career--he's 'too small,' too redneck, and made his name working for a rival company--AJ has not only flourished in WWE, he has simply dominated. The most consistently good performer on any of the WWE's myriad brands is without a shadow of a doubt AJ Styles.
He made a surprise debut at the Royal Rumble, shocking the world and bypassing the NXT developmental program that even seasoned veterans like Bobby Roode and Shinsuke Nakamura had to go trough. AJ enjoys a certain protected status simply because he is so popular and so good at what he does.
Chances of winning the Royal Rumble: 0%
Yes, you read that right. AJ will not win the Rumble, because AJ does not NEED to win the Rumble. He's already main evented Wrestlemania, and will likely do so again all on his own merits. The Rumble winner is usually someone who needs to be elevated or re-elevated, and AJ is doing fine.