In addition to the reported match involving The Undertaker, there are several other matches that have been coming up as possibilities.
F4Wonline.com reports that if Rey Mysterio is healthy, WWE has considered a match with him against Dean Ambrose. Big E. Langston versus either Mark Henry or Big Show.
Ryback working against Randy Orton also came up depending on how the rest of the card shapes up and what the company thinks the best use of Orton would be.
John Cena versus Daniel Bryan for the WWE title is still looked at to be a strong possibility at some point this summer.