#2 Jeff Hardy
This is probably the most unrealistic option as it stands right now. However, this exact feud is rumoured to be in the works for the future. And it would undoubtedly be more interesting than Reigns vs. Lesnar.
While Jeff is deeply entrenched in the tag team division as champion alongside his brother Matt, a singles push is inevitable. Jeff is one of the most popular WWE superstars of all time and was second to John Cena in merchandise sales when he left the company in 2009.
He’s fun to watch, and he’s a believable underdog, especially to someone like Brock Lesnar. What better feud could you build than the seemingly unconquerable Beast against one of the most popular yet somewhat undersized superstars ever?
Whether WWE would actually let Jeff beat Lesnar is a different story. In fact, it’s highly unlikely that they would. But the chase and the idea that maybe, just maybe Jeff could pull off the upset, would make for some incredibly compelling television.
The first time he won a world title was a memorable moment for Jeff and his fans. It would be even more memorable if he were able to accomplish this feat again against a guy like Lesnar.