#1 Aleister Black vs. The Undertaker

The rumors about Undertaker swirl every year. This time around, there's more to chew on, as he's been doing some out of character media appearances and is even set to appear at Starrcast, an event loosely affiliated with the fledgling All Elite Wrestling.
This revelation supposedly rattled Vince McMahon, to the point where WWE may be scrambling to get him on the WrestleMania card, despite having no plans for him beforehand.
Did you know a top WWE Superstar just wrestled outside the company? More details HERE
An intriguing possibility presents itself with Aleister Black now up on the main roster.
The actual match would need to be carried by Black, but the mind games leading into it could be a lot of fun to watch.
WWE seems highest on Blackout of all the recent call ups. He got a vignette before anyone did, defeated Andrade "Cien" Almas on SmackDown last week, and took the victory for him and Ricochet both times this week, flattening Shinsuke Nakamura with the Black Mass on SmackDown.
If the idea is to push these guys as stars, having Aleister Black defeat The Undertaker at WrestleMania would be about as big a rub as anyone can get.