Here are the details on the availability of all the Xbox One and Xbox 360 Games with Gold for August:

Gears of War 4 ($29.99 ERP): Available August 1 to 31 on Xbox One
Forza Motorsport 6 ($29.99 ERP): Available August 16 to September 15 on Xbox One
Torchlight ($14.99 ERP): Available August 1 to 15 on Xbox One and Xbox 360
Castlevania: Lords of Shadow ($19.99 ERP): Available August 16 to 31 on Xbox One and Xbox 360

Enjoy!!