Well this is why I created Free Gamer, to do just this, although my lists (e.g. free games list) are a bit broke atm (working on it) but still contain a lot of quality FLOSS games.
I mean... e.g... VDrift, Glest, Freeciv, Freecol, TA:Spring, I could keep going. You got too many games to maintain a list here. But good luck anyway.