Dark and hard, just the way we like it. Embossed triangles makes a nice pattern.
Source Ivan Ginev
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
White circles connecting on a light gray background.
Source Mark Collins
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
A seamless pattern formed from a sports car on clker.com. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Abstract Geometric Background 2
Source GDJ
From a drawing in 'Codogno e il suo territorio nella cronaca e nella storia'', Gio and Giarella Cairo, 1897.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
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
Square design drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
Super detailed 16×16 tile that forms a beautiful pattern of straws.
Source Pavel
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
Inspired by a drawing in 'Kulturgeschichte', Freidrich Hellwald, 1896.
Source Firkin
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
Prismatic Triangular Seamless Pattern III With Background
Source GDJ
Orange-red pattern for tiled backgrounds.
Source V. Hartikainen