#4 Roman Reigns def. The Rock (WWE WrestleMania 37)
Like the previous entry, this match depends on various factors surrounding it. Firstly, The Rock needs to get clearance from his insurers. Also, there is no point in having Roman Reigns vs. The Rock if there isn't a proper crowd present. That being said, this is the perfect story-based main event for WrestleMania 37.
Reigns has been called the Tribal Chief and the "head of the table" of the Anoa'i family, which might irk his cousin. They might not be directly related like Reigns and The Usos, but there is a story to tell between the Big Dog and The Rock. It is one of the last true dream matches WWE is yet to book.
The two have interacted a couple of times on WWE TV, particularly when The Great One raised Reigns' hand at the 2015 Royal Rumble, only to get booed out of the building. This would surely be brought up if they were to feud. The verbal battles between The Rock, Roman Reigns, and Paul Heyman would make SmackDown even more of a must-see program than it already is.
Hopefully, this match is allowed to happen because it is the perfect culmination of the Tribal Chief storyline. It would end with Roman Reigns having his hand raised. But if The Rock does not wrestle at WrestleMania, the next best option would be to see Reigns lose the Universal Championship to a current Superstar. More on that in a bit.