The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Light and tiny, just the way you like it.
Source Rohit Arun Rao
f you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
A seamless pattern with a unit cell drawn as a bitmap in Paint.net and vectorized in Vector Magic.
Source Firkin
Prismatic Abstract Geometric Background 4
Source GDJ
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
Black version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Floral patterns might not be the hottest thing right now, but you never know when you need it!
Source Lauren
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Feel free to download and use it, or see the rest of the dark background patterns that I have made. Anyway, I hope you will find something that you like.
Source V. Hartikainen
Imagine you zoomed in 1000X on some fabric. But then it turned out to be a skeleton!
Source Angelica
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
Number 5 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
A heavy hitter at 400x400px, but lovely still.
Source Breezi
A pale yellow background pattern with vertical stripes. The stripes are partially faded. I think this background image turned out pretty well, especially those faded stripes.
Source V. Hartikainen
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