A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
First pattern tailor-made for Retina, with many more to come. All the old ones are upscaled, in case you want to re-download.
Source Atle Mo
Prismatic Groovy Concentric Background 3
Source GDJ
Seamless pattern the basic tile for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This one is amazing, truly original. Go use it!
Source Viahorizon
A version without colours blended together to give a different look.
Source Firkin
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
Dark and hard, just the way we like it. Embossed triangles makes a nice pattern.
Source Ivan Ginev
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Submitted in a cream color, but you know how I like it.
Source Devin Holmes
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
It’s an egg, in the form of a pattern. This really is 2012.
Source Paul Phönixweiß
Subtle scratches on a light gray background.
Source Andrey Ovcharov
An abstract texture of black metal pipes (seamless).
Source V. Hartikainen
The original enhanced with one of Inkscapes's filters.
Source Firkin
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
Colourful background achieved with gradient fills.
Source Firkin
Light gray paper pattern with small traces of fiber and some dust.
Source Atle Mo
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin