I believe that the renders from games are owned by the original company that made the game (i.e. microsoft and bungie if you were talking about halo). I'm not positive if the people who made the renders (the modeller, animator etc.) own the rights to it. Being that this board doesn't have restrictions on copyright enfringement (game renders and a few things from deviantart have been used) I doubt you'll find many people here who know where you should go. If your looking for free stock photos, I suggest http://www.sxc.hu but it doesn't sound like thats what youre looking for. Good luck in your hunt for copyright free material.