I spent much of yesterday making a selection of weapons for my new game, I've been using cycles now that I actually have a modern graphics card, and the procedural textures you can create with the node system are amazing. All weapons shown use procedurals only.
These aren't going to be added to the free sprites section just yet, but they may become free sprites in the future when the game is released, so if you're interested in using these, keep watching this area.
Edit: Update, the game is cancelled, these sprites are now CC-By international 4.0 licensed with credit to "millionthvector" or "Alan Guyant".