#3 The Undertaker

The Man from Death Valley is practically forever. His origins precede the Attitude Era, but like Madonna, he has constantly changed with the times to stay relevant. It was actually during that era that The Undertaker provided new glimpses into his persona as The Prince of Darkness and his eventual transformation into the American Badass.
While he now wrestles only a handful of times and missed last year's WrestleMania, it's only a matter of time that he appears in 2020 to wrestle whether that be at WrestleMania 36 or one of the Saudi Arabia shows.
It should be noted that recent reports suggest that The Undertaker is negotiating a spot on the WrestleMania 36 card, though it's unclear who his opponent will be if it does actually happen. Most WWE fans would love to see him in a feud with The Fiend, but it's highly doubtful that will happen at WrestleMania.
At age 54, The Undertaker is limited compared to the days when he could go bell-to-bell, but if he does wrestle, it will be against a much younger opponent.
Becky Lynch has been challenged HERE.