Company of Heroes 2 is free to own if you get it before Nov. 17th: https://store.steampowered.com/app/231430/Company_of_Heroes_2/
And the same applies (free to own if you get it before Nov. 18th) to the Crusader Kings II: Sword of Islam expansion, but you need to own CK2 first: https://store.steampowered.com/app/203778/Expansion__Crusader_Kings_II_Sword_of_Islam/