Here's a bluish gray striped background pattern for use on web sites.
Source V. Hartikainen
You know I’m a sucker for these. Well-crafted paper pattern.
Source Mihaela Hinayon
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
From a drawing in 'A Rolling Stone. A tale of wrongs and revenge', John Hartley, 1878.
Source Firkin
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
A seamless pattern with a unit cell drawn as a bitmap in Paint.net and vectorized in Vector Magic.
Source Firkin
A seamless striped fabric-like texture colored in a dark reddish brown color.
Source V. Hartikainen
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
A bit strange this one, but nice at the same time.
Source Diogo Silva
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Inspired by a pattern I saw in a 19th century book. This seamless pattern was created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
A seamless pattern the starting point for which was a 'light rays' rendering in Paint.net.
Source Firkin
Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
In the spirit of WWDC 2011, here is a dark iOS inspired linen pattern.
Source Atle Mo
A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
Seamless Light Background Texture.
Source V. Hartikainen
Zero CC tileable wood texture, made by me procedurally in Neo Texture Edit.
Source Sojan Janso
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
A pattern drawn in Paint.net and vectorized in Inkscape.
Source Firkin
Just like your old suit, all striped and smooth.
Source Alex Berkowitz
Non-seamless pattern drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Greyscale version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin