A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
A seamlessly tile-able grunge background image.
Source V. Hartikainen
This white background pattern has a seamless grunge style texture. Here's a white grunge style background pattern. Use it as a tiled background image on web sites or for other purposes.
Source V. Hartikainen
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
A dark brown fabric-like background texture with seamless pattern of winding stripes.
Source V. Hartikainen
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Not the Rebel alliance, but a dark textured pattern.
Source Hendrik Lammers
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
An abstract Background pattern of purple twisty patterns.
Source TikiGiki
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Prismatic Abstract Line Art Pattern Background
Source GDJ
Colour version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
Geometric triangles seem to be quite hot these days.
Source Pixeden
A seamless pattern with wide vertical stripes colored in pale yellow.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
A free repetitive background with a dark concrete wall like texture. This one may be used in dark web site designs.
Source V. Hartikainen
Everyone needs some stardust. Sprinkle it on your next project.
Source Atle Mo
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
A repeating background for websites with a texture of black groove stripes.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin