September's Games with Gold has Earthlock: Festival of Magic and Assassin's Creed Chronicles: China on Xbox One.
Earthlock is free to download during the month of September. Assassin's Creed Chronicles: China is a free download from 16th September to 15th October.
Xbox 360 gets Forza Horizon (1-15 September) and Mirror's Edge (16-30 September). Both games are available to play on Xbox One via with Backward Compatibility.
Earthlock is a turn-based role-playing game. Assassin's Creed Chronicles: China is a 2D side-scrolling spin-off.