I’m always looking for a texture, a bit of this or that to go with something else I’m making, and I’ve spent a lot of time searching the interwebs for them.  Here’s a few sites you might find useful for your texture needs.  As always, please check the usage rules before you use them in a project.

MorgueFile

PixelPoke

The Texture Studio

Noctua Graphics

Image*After

Psionic3D

Filter Forge

Dawid Michalczyk