#2 AJ Styles
Whilst the WWE are hoping to re-sign the Phenomenal One, the reportedly slow negotiations between AJ Styles and the company are hard to ignore.
Debuting in shocking fashion at the 2016 Royal Rumble, the former TNA star has done incredibly well in WWE, holding the WWE Championship twice, with one of these reigns lasting over a year.
Signing to a three-year contract, it is public knowledge that Styles' current deal with WWE expires in the first half of 2019, and it's up to Styles if he wants to re-sign.
With the company reportedly offering a huge contract, including a more relaxed schedule akin to fellow SmackDown Live Superstar Randy Orton, it looks like it'd be foolish for Styles to leave.
With that said, AJ could be a success in any promotion, and leaving could allow him more freedom.