Back in 2011, Bethesda released a class based, parkour oriented FPS called "Brink". It wasn't much of a critical success at launch. And as time moved on, it kept losing its player base. Making the multilayer aspect of the game almost dead.
Undoubtedly the devs thought that something must be done. And so they turned Brink into free-to-play. This initiative has already garnered results. According to Steam Charts, Brink's player base has jumped from close to no players to well above two thousand players. Yes, the 6 year old game is coming back from the dead!
You can get it on Steam. But remember, only the base game is F2P, not the DLCs.