I know this isn't strictly free but it's helluva cheap (at least it is in £ ). Doesn't seem worth starting a new thread for.
Requiem Avenging Angel ( currently £1.49 on GOG)
https://www.gog.com/game/requiem_avenging_angelIt's a Quake 2/3 ish era/generation game where you (the protagonist) are an Angel, descending to a dystopian Earth to thwart the forces of evil trying to take over. A flawed classic, to be sure, but it does have some really good moments and some interesting concepts/visuals.
Also, people in this community will recognise some of the sound effects that I may, or may not, have ripped for some of my mods in the past.
