Black brick wall pattern. Brick your site up!
Source Alex Parker
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
It’s okay to be square! A nice light gray pattern with random squares.
Source Waseem Dahman
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
You know I’m a sucker for these. Well-crafted paper pattern.
Source Mihaela Hinayon
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo