#3 Goldberg
Well, Goldberg is already advertised to headline the Hall of Fame class of 2018 at this year's WrestleMania but, considering that the WWE is likely to put him on the forefront of the Andre the Giant Memorial Battle Royal, it could be a definite shocker. The company is hell-bent on promoting the documentary on the life of the popular Giant and from a business standpoint, bringing Goldberg to compete could bring a lot of viewership from the casual fan base.
There is a possibility that this happens and could be met with an outstanding response if 'the Icon' shows up in his gear and, annihilates his opponents to win the Battle Royal. Well, there could be conflicting opinions regarding his return but, the company will push him to elevate the marketability of the event.