Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
This one resembles a black concrete wall when is tiled. It should look great, at least with dark website themes.
Source V. Hartikainen
Seamless pattern the basic tile for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Here's a new background image for websites with a seamless pink texture. It should look beautiful with website themes where light pink background is needed. The background is seamless, therefore it should be used as a tiled background.
Source V. Hartikainen
Prismatic Chevrons Pattern 5 With Background
Source GDJ
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
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
Prismatic Geometric Pattern Background
Source GDJ
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin