Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
Black & white version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
This background has abstract texture with some similarities to wood.
Source V. Hartikainen
A seamless pattern the starting point for which was a 'light rays' rendering in Paint.net.
Source Firkin
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
Everyone needs some stardust. Sprinkle it on your next project.
Source Atle Mo
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
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
This background pattern contains worn out colorful stripes as a texture.
Source V. Hartikainen
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
An attempt for cleaning up the original image in a few steps.
Source Lazur URH