#6 Sami Zayn
Sami Zayn had an incredible run down in NXT, claiming the NXT Championship in an incredible bout with Neville, but for one reason or another, he hasn't been given a significant push since arriving on the main roster. Zayn was once the best babyface in the WWE, and many saw him as the next Daniel Bryan, but like Bryan, his career seems to be going much better as a heel, and with his recent performances on RAW, it's only a matter of time until there's gold around his waist.
Since his return, Zayn has been a master of getting heat from the WWE Universe, and you can't help but be impressed by it, and combining this with his wrestling ability, it's clear he's trending upwards. If Sami doesn't taste gold by the end of 2019, it's hard to see him sticking around in WWE for much longer, because he deserves better, but if this heel run continues trending the way it is, he'll no doubt find success.