#1 John Cena

Finally, we get to the former face of WWE and now Hollywood star John Cena. The list of reasons as to why he could return is almost endless just based on rumors alone. WrestleMania is in Tampa and he has come out and said himself he would like to be a part of the show. You have to figure that if Cena wants a match he will likely get a match.
You may ask who could he face? He has a history with so many Superstars and could almost name the same two I just did for The Undertaker. However to go in a different direction he could face Daniel Bryan. Bryan has now lost to The Fiend twice and needs a dance partner at WrestleMania and has plenty of history with the leader of the Cenation.
Cody Rhodes' uncle is a WWE Hall of Famer. More details HERE.
If he were to return to the Raw side, I could see him in a match with Bobby Lashley. Lashley coming off a big feud win over Rusev and has had some of the most-watched segments being with Lana could use a spotlight match with Cena. This could also give Cena an opportunity for victory while still elevating Lana and Lashley in the process.