From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Green Background Pattern
Source V. Hartikainen
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
A seamless texture of an abstract wall colored in shades of light orange brown.
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
Remixed from a drawing in 'Some account of the Worshipful Company of Ironmongers', John Nicholl, 1866.
Source Firkin
Prepared mostly as a raster in Paint.net and vectorised.
Source Firkin
Here's a dark background pattern that contains a steel grid pattern as a texture. Use it as a website background or for other purposes. It's free!
Source V. Hartikainen
A dark brown fabric-like background texture with seamless pattern of winding stripes.
Source V. Hartikainen
I asked Gjermund if he could make a pattern for us – result!
Source Gjermund Gustavsen
Remixed from a drawing in 'Line and form", Walter Crane, 1914.
Source Firkin
Psychedelic Geometric Background No Black
Source GDJ
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
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.