The image depicts a seamless pattern of a tortoise in tortoiseshell (hexagon).
Source Yamachem
There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Zero CC tillable hard cover red book with X shape marks. Scanned and made by me.
Source Sojan Janso
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
In the spirit of WWDC 2011, here is a dark iOS inspired linen pattern.
Source Atle Mo
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
Remixed from a drawing in 'Jezebel's Daughter', Wilkie Collins 1880
Source Firkin
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
The classic notebook paper with horizontal stripes.
Source Are Sundnes
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless pattern with a unit cell drawn as a bitmap in Paint.net and vectorized in Vector Magic.
Source Firkin
Number five from the same submitter, makes my job easy.
Source Dima Shiper
A classic dark tile for a bit of vintage darkness.
Source Listvetra
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
Colour version of the original pattern.
Source Firkin