#2 Drew McIntyre

Should Braun Strowman win the Universal title from Brock Lesnar at the Royal Rumble, the odds of McIntyre winning the Rumble match increase exponentially. He's the top heel on Raw with Lesnar barely on the show and has the support of those in charge.
McIntyre has also been great in his role as a destructive and brutal heel since his return to the main roster. There's a reason why he's been booked so strongly since his return, and a showing in at least the final four of the Rumble match is close to a sure thing.
I'm expecting McIntyre to have a huge showing in the match, eliminating several superstars along the way. He might not break Roman Reigns' record of eliminations, but he's going to be one of the featured superstars in the match.
When the dust is cleared, though, don't be surprised if the 'Scottish Psychopath' wins the Royal Rumble. He was one of the early betting favourites when the odds were first released, so he's still a threat to win it.