Currently free on gog + a bunch of games on sale worth checking. https://www.gog.com/game/carmageddon_tdr_2000
https://www.makewarnotlove.com/ Link your steam account & get two free sega mega drive games for it atm. Streets of rage & Revenge of the shinobi & each reached event gives out games/dlc packs for everyone if the specific games played reach a certain amount of time between everyone that has been joining the campaign. Been getting sale codes so far on various sega titles rather then actual games.
For those who havent gotten a chance too pick up amnesia its currently free it seems. http://store.steampowered.com/app/57300/Amnesia_The_Dark_Descent/
The Darkness II is free on humble bundle at the moment. https://www.humblebundle.com/store/..._layout_index_1_layout_type_twos_tile_index_1
http://store.steampowered.com/app/203770/Crusader_Kings_II/ Free permanent copy of Crusader Kings II!
https://www.humblebundle.com/store/..._satellitereign_storefront&utm_content=Banner Satellite Reign Free on humble bundle
this is free on humble bundle atm https://www.humblebundle.com/store/galactic-civilizations-ii-ultimate-edition?partner=pandascorner
Unreal gold free on gog.com classic fps game that's now 20 years old. https://store.steampowered.com/app/13250/Unreal_Gold/
https://store.steampowered.com/app/823130/Totally_Accurate_Battlegrounds/ free for i think 80 more hours as i don't know the time they started giving this for free if it was today or yesterday & there's no time limit counter atm.
https://store.steampowered.com/app/391720/Layers_of_Fear/ layers of fear once again free on steam for a limited time.