August Games w/ Gold: Slime Rancher or Trials Fusion (Xbox One) or Bayonetta or Red Faction: Armageddon (Xbox 360) Free (Xbox Live Gold Required) *Starts 8/1*

Microsoft
August Games w/ Gold: Xbox Live Gold Membership Required

• Slime Rancher (Xbox One) Free from 8/1-8/31
• Trials Fusion (Xbox One) Free from 8/15-9/15
• Bayonetta (Xbox 360) Free from 8/1-8/15
• Red Faction: Armageddon (Xbox 360) Free from 8/16-8/31

More Details here