This was formed by distorting an image of a background on Pixabay.
Source Firkin
This could be a hippy vintage wallpaper.
Source Tileable Patterns
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
This is a remix of "geometrical pattern 01".
Source Yamachem
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
A seamless pattern formed from miutopia mug remixes on a tablecloth.
Source Firkin
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
More tactile goodness. This time in the form of some rough cloth.
Source Bartosz Kaszubowski
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Zero CC tileable cork floor, photographed and made by me. CC0
Source Sojan Janso
Dark pattern with some nice diagonal stitched lines crossing over.
Source Ashton
Paper model of a tetrahedron. Modelo de papel de um tetraedro.
Source laobc
Heavily remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
A seamless pattern recreated from an image on Pixabay. It is reminiscent of parquet flooring and is formed from a square tile, which can be recovered in Inkscape by selecting the ungrouped rectangle and using shift-alt-I together.
Source Firkin
This reminds me of Game Cube. A nice light 3D cube pattern.
Source Sander Ottens
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
An alternative colour scheme to the original seamless pattern.
Source Firkin