Get the Battlefield 1 Premium Pass for free.
Get Dead Space from Origin "on the house". https://www.origin.com/usa/en-us/store/free-games/on-the-house
Get THE KING OF FIGHTERS 2002 from GOG for a limited time. https://www.gog.com/game/the_king_of_fighters_2002
GOG also has several "connect" games you can grab if you already have the...
Grab "Fallout: A Post Nuclear Role Playing Game" free from Steam. You should be able to add it to your library without actually installing the game.
The deal is only live until until September 30th at...
Get Psychonauts Steam key (pc game) for free from Humble Bundle. FREE for a limited time (48 hours)!
* Note: You must redeem your free Psychonauts key by 10AM Pacific on Saturday, September 30th, 2017!
Though you have to hand over an email address, which may be personally identifiable. Seems to be the thing to do these days - give away your old software in exchange for an email address.
Make sure you uncheck that "Please send me ..." checkbox.
Get Tropico 4 Steam PC game for free from the Humble Store. This deal ends in 2 days!
This game has a 90% + rating on Steam. http://store.steampowered.com/app/57690/