#3 Seth Rollins
The Kingslayer has carried Raw on his back for the whole year. Rollins has put on great matches every week and has truly gotten the fans behind him. He is currently the Intercontinental Champion.
He is currently involved in a feud against his former SHIELD brother, Dean Ambrose. Although he's in a feud with Dean Ambrose, according to reports Seth Rollins is clearly being considered as an opponent for Lesnar at WrestleMania 35. He also cut a promo on Raw after Crown Jewel and criticized Lesnar's title victory at Crown Jewel.
If he will face Lesnar at WrestleMania 35 he will first have to lose the Intercontinental title, and he could lose the title at TLC where he will be facing Dean Ambrose. After that, he could win the Royal Rumble and challenge Lesnar for the Universal Title.
If WWE decides to pit up Rollins against Lesnar at WrestleMania 35, we can be sure that they are going to create an exciting and amazing rivalry.