Jensen Ackles appeared as Dean Winchester in the Supernatural spinoff The Winchesters. There, the character gave equipment and advice to young versions of his parents, which should create a different future for the Sam and Dean of that world. With Ackles' main version of Dean having died at the end of Supernatural, there is a chance that a potential return of Supernatural for season 16 would focus on the alternate versions of Sam and Dean from The Winchesters' world, or at least have that Dean meet with Jared Padalecki's main Sam Winchester, which I think would be interesting to see.