#2. Balor Club reunites
Finn Balor could always join forces with his former Bullet Club allies to dethrone the Beast. Karl Anderson and Luke Gallows are sitting on Smackdown LIVE without doing anything worthwhile in the last few weeks. Since the Royal Rumble is a co-branded event and both the Good Brothers could be making an appearance for the 30 man Royal Rumble match, it is entirely possible that Balor may call for reinforcements if that is the best way to reclaim the Universal Championship.
However, there is a reason why Brock Lesnar has been the Universal Champion for so long. WWE built Lesnar as the unbeatable monster heel for one reason only - to give the eventual superstar who beats Lesnar a huge rub and propel him to the main event. All four methods mentioned previously are in direct contradictions with this reason. Thus, we need a fifth scenario that ticks all the boxes.