#1 Killian Dain
In my opinion, out of all the wrestlers in NXT, Killian Dain is the most likely NXT superstar to enter next year's Royal Rumble.
Think about it - Dain enters the Rumble, the commentators say "how can anyone POSSIBLY throw this guy out?!?", he lays waste to a bunch of dudes, faces off with Bray Wyatt, Finn Bálor, and/or Braun Strowman, then he's finally eliminated by every guy in the ring.
Check out which wrestler EC3 finds cute RIGHT HERE
Pretty believable, right? That's classic WWE tropes for you.
Anyhow, the former Big Damo's entrance in the 2018 Royal Rumble would be an excellent way for WWE to re-introduce him to the mainstream audience following his impressive showing in last year's Andre The Giant Memorial Battle Royal. Plus, I'm not sure that they have much for him to do in NXT. That is unless they're thrusting him directly into the NXT Championship picture, which is a bit unlikely considering his focus on tag team wrestling as of late. But, again, I'm no fortune teller.
All I can say is, one of the main narratives of the Royal Rumble match is written for guys like Killian Dain, and I think that he'd make a worthy addition to the match and to the main roster.