I'm usually quite up-to-date on the whole free game on Steam business, which is why I have so many games. The following links have been used by me to get the game, and usually don't require anything (unless otherwise mentioned by me).
http://store.steampowered.com/app/304930 - Unturned
http://store.steampowered.com/app/277970 - DLC for Tom Clancy's Ghost Recon Phantoms (F2P), (valid 7/11/14 - 7/13/14)
http://www.pcgamer.com/2014/07/09/free-steam-key/ - Really Big Sky, requires Twitter account and giving out email (for the key) NOTE: I have had some issues getting this key (valid until 7/16/14, or all million keys have been given out).
http://www.indiegala.com/giveaways - Woodle Tree Adventures* , requires an Indiegala account
https://www.origin.com/en-in/store/buy/peggle/mac-pc-download/base-game/standard-edition - Peggle, only on Origin (valid until 8/5/14)
http://www.psyonix.com/BC2/Invite/RocketLeagueSignup.php - Rocket League beta sign-ups, requires an email.
http://www.buttopaintauniverse.com/ But to Paint a Universe (on Steam but still needs to be Greenlit)
* = Has trading cards
There are probably others that I have missed, but some titles are giving away free keys to those who vote and perhaps do some other requirements, but because I haven't gotten a key from any of them (nor have any of them been Greenlit, I'm putting them off).
Also, SteamGifts is a great way to get free games. I ended up getting Command and Conquer 3: Red Alert Uprising on Steam from entering a giveaway. You have to provide an email and have over 150.00$ worth of games on Steam I believe, but I check the forums for free stuff and enter giveaways whenever I can.







