https://www.overclock3d.net/news/software/amazon_s_giving_away_some_excellent_games_this_month_though_prime_gaming/1
 
If you are subscribed to Prime, you will be given free copies of PC games every month
Amazon's Prime subscription has a little known benefit for PC gamers. Every month, Amazon gives away free copies of PC games to their subscribers though their Prime Gaming service, giving Prime Subscribers a great way to expand their PC gaming libraries and catch up on both old and relatively new PC games. 
Recent months have seen games like Star Wars Jedi: Fallen Order and Mass Effect Legendary Edition become available for free though the service. This month, Amazon's giving away free copies of seven PC games, with the most noteworthy being Middle-Earth: Shadow of Mordor, Football Manager 2022, and Assassin's Creed Origins. 
All of these games will be available for free though Prime for the next 28 days. These free games are also available for free to people who are using their Amazon Prime free trial. New subscribers can get a free 30-day trial of Amazon Prime here.
Below are the games that are available for free to Amazon Prime subscribers.
- Middle-Earth: Shadow of Mordor - Game of the Year Edition
- Football Manager 2022
- Assassin's Creed Origins
- Castle on the Coast
- Defend the Rook
- The Dig
- We, The Revolution
 
Amazon Prime subscribers can redeem free PC games though Prime Gaming here.
 
If you're a subscriber go get these free games!

Some are stand alone (Shadow of Mordor), but too much linking of accounts for my tastes for many of the items.