We already knew that Earthlock: Festival of Magic will launch as a Game with Gold, and now we know the rest of the game's Gold members will get to download for free in September:
• Earthlock: Festival of Magic the entire month
• Assassin's Creed Chronicles: China from September 16th to October 15th.
• Forza Horizon through September 15th.
• Mirror's Edge from September 16th through September 30th.