#1 Brock Lesnar vs Roman Reigns vs The Undertaker
Just because the thought of Reigns vs Lesnar might be a bit underwhelming, it does not mean 'The Big Dog' can not be part of something epic; his in-ring work is very solid and he has put on some great matches.
This one would be a true story of redemption and a great way to close the Undertaker's storied career.
The story hear would be The Undertaker having one last chance to defeat the two men that beat him at WrestleMania; he could win the Universal title, and then leave it in the ring before saying his last goodbye, having proved he is indeed the Phenom. He could do it with a win against the two men that humbled him on the grandest stage of them all.