Jay Garrick
As we’ve seen before, Jay Garrick is all about sacrifice and willing to take one for the team if necessary. With Barry trapped in the Speed Force, Jay could take his place in Team Flash and help look after Central City with Wally West. After all, two Flashes are better than one.
Think of Jay and Wally as the equivalents of Bruce Wayne and Terry McGinnis in Batman Beyond, with the older, wiser crime-fighter providing much-needed guidance to the young whippersnapper. Heck, with Jay and Joe West as mentors, Wally really has no excuse in becoming the best Flash possible.
Although, we must admit this suggestion is a little bit of a selfish choice, because we just want more of John Wesley Shipp in the series. He’s easily the highlight of every episode he appears in and injects a healthy dose of nostalgia and fun into his role(s).