A seamless pattern formed from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
A seamless pattern of "sewn stripes" colored in light gray.
Source V. Hartikainen
This light blue background pattern is quite pleasing to the eye, it consists of a tiny rough grid pattern, which is seamless by design. That's it, if you like the color, you can use this seamless pattern in a web design without making any further modifications to it.
Source V. Hartikainen
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
A brown metallic grid pattern layered on top of a dark fabric texture. It should look great when using as a tiled background on web pages, especially blogs.
Source V. Hartikainen
Prismatic Triangular Background Design Mark II 5
Source GDJ
This ons is quite old school looking. Retro, even. I like it.
Source Arno Declercq
Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Redrawn based on a drawing in 'По Сѣверо-Западу Россіи' Konstantin Sluchevsky, 1897.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A white version of the very popular linen pattern.
Source Ant Ekşiler
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Your eyes can trip a bit from looking at this – use it wisely.
Source Michal Chovanec
Greyscale version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin