From an image on opengameart.org shared by rubberduck.
Source Firkin
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
A background tile of dark textile. Made this a long time ago and just now decided to publish it.
Source V. Hartikainen
The name is totally random, but hey, it sounds good.
Source Atle Mo
Tile-able Dark Brown Wood Background. Feel free to use it as a background image in your designs or somewhere on the web. By the way, the color seems to be close to Coffee Brown.
Source V. Hartikainen
This is sort of fresh, but still feels a bit old school.
Source Martuchox
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo
Green Web Background, Seamless tile.
Source V. Hartikainen
Here's an yet another seamless note paper texture for use as a background on websites.
Source V. Hartikainen
Embossed lines and squares with subtle highlights.
Source Alex Parker
Inspired by a pattern found in 'A General History of Hampshire, or the County of Southampton, including the Isle of Wight', Bernard Woodwood, 1861
Source Firkin
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.
Source Lazur URH
Sweet and subtle white plaster with hints of noise and grunge.
Source Phil Maurer
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Here's a dark background pattern that contains a steel grid pattern as a texture. Use it as a website background or for other purposes. It's free!
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin