4. The Rock
Dwayne "The Rock" Johnson is arguably the most famous WWE Superstars of all time, even though he isn't famous just for wrestling. Despite not competing as a full-time wrestler since 2004, the Rock still manages to get a reaction that only a few can. Despite his age, the Rock is still in incredible shape and is capable of putting on a quality match.
Thus, his last match at WrestleMania 32 came as a surprise to many when he defeated Eric Rowan in a mere six seconds. The Rock then announced his retirement in 2019. However, it is highly unlikely that a Superstar such as The Rock would go out in such an anti-climatic way.
The Rock still could be a part of many exciting feuds in WWE, most notably with Roman Reigns. Even Reigns has not shied away from speaking on this topic.
Hence, it is very likely that the Rock will return to the squared circle once again and possibly win the World Championship along the way.