Graphics Gems Repository is a good place to start with the Graphics Gems series. Also check out Real-Time Rendering Resources for a good set of links (and a pretty good book as well). Texturing and Modeling, Third Edition: A Procedural Approach (The Morgan Kaufmann Series in Computer Graphics): David S. Ebert, F. Kenton Musgrave, Darwyn Peachey, Ken Perlin, Steve Worley: 9781558608481: Amazon.com: Books is an excellent book on generating content that isn't terribly focused on just graphics basics.