Steam has got the following freebies:
Tomb Raider (2013). Free until 23 March.
Lara Croft and the Temple of Osiris. Free until 23 March.
Deiland. Free until 23 March.
Headsnatchers. Free until 22 March. I don’t know anything about the above 3 games, but Headsnatchers is a weird game that suffers terribly from not having enough players online. I cannot try local multiplayer, so maybe that is where the real fun is. The one game mode for single-player has been quite boring and frustrating for me.