There are! Try ShareCG.com for one (make sure you check the button for shared, as there are some things for sale). Turbosquid.com sometimes has things. Renderosity.com has a free section. Other than that, just search for free 3D models. You can also make your own in Hexagon from Daz3d.com (free program), Blender, Wings3D, Curvy3d (paid program) and a couple of others.