Few months ago I was playing some new-ish Quake maps on lunchbreaks and I kept seeing the same amazing textures showing up in map after map. They're a free set from a guy called Benjamin Hale, and they are superb. While the structural textures are maybe a little more Heretic/Hexen flavoured in style they could work in a hell setting, and there are also tons of fantastic cliff, rock and brick textures.
Full-colour exports are available, plus a Quake texture wad. Even if you don't ta