These are some map textures I've been working on lately that are released under the GPL and/or CC-by-sa:
Filth Texture Pack

~120 rusty/dirty red/yellow/grayish textures.
More info and download on my website.
Babel Texture Pack

A mix of different tiling textures, not really centered around a particular theme.
Again, more info and download on my website.
Hopefully some of these will come in handy to someone. Enjoy
