VideoCardz.com, which is often the starting point of rumors, has released a new list. The list is their March post of 2014-2015 Mantle supporting games, which includes existing games with Mantle support, announced games which will have Mantle support, and announced games with pending Mantle support.
|Battlefield 4||DICE, Frostbite Team||Frostbite 3|
|Thief||Eidos Montreal, Nixxes Software||Unreal Engine 3|
|Plants vs. Zombies: Garden Warfare||PopCap Games, Frostbite Team||Frostbite 3|
|Sniper Elite 3 (Mantle not yet available)||Rebellion||Asura|
|Unreleased (Confirmed Mantle support)|
|Sid Meier's Civilization: Beyond Earth||Firaxis Games||LORE|
|Star Citizen||Cloud Imperium Games, Behaviour Interactive||CryEngine|
|Dragon Age: Inquisition||BioWare, Frostbite Team||Frostbite 3|
|Battlefield: Hardline||Visceral Games, Frostbite Team||Frostbite 3|
|Offworld Trading Company||Mohawk Games, Oxide Games||Nitrous Engine|
|Mass Effect (untitled)||BioWare, Frostbite Team||Frostbite 3|
|Mirror's Edge (untitled)||DICE, Frostbite Team||Frostbite 3|
|Star Control||Stardock, Oxide Games||Nitrous Engine|
|Star Wars: Battlefront||DICE, Frostbite Team||Frostbite 3|
|Rise of the Tomb Raider||Crystal Dynamics, Nixxes Software||Crystal|
|Dying Light||Techland||Chrome Engine 6|
|Unannounced title||Oxide Games||Nitrous Engine|
|Unreleased (Mantle support pending)|
|Homefront: The Revolution||Crytek||CryEngine|
|Call of Duty: Advanced Warfare||Treyarch||in-house|
|Alien: Isolation||Creative Assembly||in-house|
|Elite: Dangerous||Frontier Developments||Cobra Engine|
|Grand Theft Auto V||Rockstar Games||R.A.G.E.|
|Lara Croft and the Temple of Osiris||Crystal Dynamics, Nixxes Software||in-house|
|Kingdom Come: Deliverance||Warhorse||CryEngine|
|Sleeping Dogs: Triad Wars||United Front Games||in-house|
Tables Courtesy of VideoCardz.com
Within this list is one particularly notable entry: GTA V. It was determined a couple of weeks ago that GTA V would be getting a second launch when it comes to the PC, Xbox One, and PlayStation 4. The list shows that Mantle support is still pending for the game. This does not mean that the game will definitely have Mantle support, but rather that there is a good chance it might, as Rockstar has been granted access to the Private Beta of Mantle.
The list also mentions an untitled Mass Effect game, which indirectly confirms that there is a new Mass Effect game coming.
Hopefully, there will soon be an official announcement from AMD to confirm this. Until then, this is still a rumor, and despite hoping that there is truth in it, we should all still take it with a grain of salt. VideoCardz.com is known to get stuff right on a regular basis though, so there may be some merit to this rumor.