#2 Adam Cole (May not move to the WWE main roster)

Former WWE NXT Champion Adam Cole has done it all in NXT.
Since debuting on the black and gold brand at NXT TakeOver: Brooklyn III in 2017, the former leader of The Undisputed Era has become synonymous as the face of NXT.
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During the past four years Adam Cole has become the longest reigning NXT Champion in WWE history, the inaugural NXT North American Champion, a former NXT Tag Team Champion and the second ever NXT Triple Crown Champion.
During this period of time there have been numerous reports and rumors about Adam Cole possibly leaving NXT and debuting on either Monday Night RAW or Friday Night SmackDown. Yet, this is yet to happen.
It is clear that Adam Cole has a great desire to stay on NXT and vice-versa, as NXT's seen it's best years with the Panama City Playboy on the roster.
While Monday Night RAW and Friday Night SmackDown would certainly benefit to have a superstar the caliber of Adam Cole on the show, one must question if the former NXT Champion could follow in the footsteps of other past NXT Champions who have not been able to successfully transition to the WWE main roster.
Perhaps Adam Cole is just too important to the black and gold brand to let go. Therefore, it certainly is possible that now as a solo act, Adam Cole continues to stay on NXT for the foreseeable future.