This list should have a link to Reiner’s Tilesets: http://www.reinerstilesets.de/

Thanks for the tip! Just added it :)

We have a weekly updated section for original free game assets that could go on the list:
http://www.indiegamedesigner.com/category/free/

Hi OpenGameArt is fantastic thanks! I just found another gem by following links from them:

http://www.blendswap.com/

lots of royalty-free 3D models and tools

Added! Thanks :)

Your last link under 2D Graphics doesn’t work… Should go to http://ails.deviantart.com/art/420-Pixel-Art-Icons-for-RPG-129892453 but a quick look at the HTML shows that you missed the = in the

Thanks for pointing it out :) I’ve just fixed it.

I found that in the 3D models category, there are quite a few indie-friendly publishers. They just tend to hide pretty well behind all the big sites like turbosquid and the3dstudio:

http://3dfoin.com/ (lots of animated monsters and player characters)
http://www.3drt.com/ (model sets suitable for mobile games)
http://arteria3d.com/ (high quality characters and props)
http://www.dexsoft-games.com/ (more HQ characters and props)
http://mr-necturus.com/shop/

Most of them even offer their models in version ready-made for popular indie 3D engine choices like Blender (BGE), Ogre3D and Unity.