Mr. McMahon vs. Mick Foley: WrestleMania X-Seven

I.R.S., The Headshrinkers, Rick Martel and Jeff Jarrett vs. Tatanka, The Smoking Gunns, Bob “Spark Plug” Holly and The 1-2-3 Kid: WrestleMania X

Ric Flair vs. Hulk Hogan — WWE Championship Match: WrestleMania VIII

Mike Tyson vs. Triple H — Boxing Match: WrestleMania X-Seven

Razor Ramon vs. Goldust — Miami Street Fight: WrestleMania XII

Big Show vs. Shaq: WrestleMania XXVIII

John Cena vs. Jay Z & Fabolous — Battle Rap: WrestleMania XIX

Kane vs. X-Pac: WrestleMania 2000

Mankind vs. Vader: WrestleMania 13

“Stone Cold” Steve Austin vs. Hollywood Hogan: WrestleMania X8

http://www.wwe.com/shows/wrestlemania/10-wrestlemania-matches-that-almost-happened

Other than the first and last, I don't feel sad that any of these didn't happen.

I quickly said "ew" when I saw the battle rap one. Not because Battle Rap sounds stupid to me, but because i loath Jay Z and Fabolous.