Most resources are either totally free, or free for commercial use as long as the author is credited. Can be used as a base for own levels. Textures from the Qoole WAD Collection by various artists. 8-Bit textures, can easily be converted to true colour. MDL format, mostly 8-bit skins.
All models are free for commercial use as long as the author is credited.
The 3D GameStudio standard texture collection with 92 true colour textures in much better quality than the old A4 8-bit standard textures. Free for commercial use in GameStudio applications. The 500 prefabricated 3D objects that come with 3D GameStudio. They use the true colour textures from the new standard.wad above. If you have an old A4 version, just replace the old prefabs folder with this new one.