Tags are good and all, but imo we also need "Categories".
I know we have categroies like 3d,2d,texture etc. but one more layer of categories could be really usefull.
Characters,Vehicles,Props,Architecture... etc for 3d
Ui,Portraits,Sprites, Tilesets... etc for 3d
Ui, Ambient, Voice... etc for sounds
Concrete,leather,metal,nature,Texture maps for textures
Also this is CC-BY only.
http://www.unbruco.it/offcircle/risorse_en.html -> bottom of the page
fragmotion uses UGH
fragmotion can export to/import from a vast variety of formats, sort of like milkshape but more animation oriented.