This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Honestly, who does not like a little pipe and mustache?
Source Luca Errico
A series of 5 patterns. That’s what the P stands for, if you didn’t guess it.
Source Dima Shiper
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
A seamlessly repeating background pattern of wood. The image is procedurally generated, and, I think, it's turned out quite well.
Source V. Hartikainen
Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
A nice one indeed, but I have a feeling we have it already? If you spot a copy, let me know on Twitter.
Source Graphiste
The image is a design of blue glass.How about using it as background image?
Source Yamachem
Sharp pixel pattern, just like the good old days.
Source Paridhi
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
Background formed from the original with an emboss effect
Source GDJ
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Sharp pixel pattern, just like the good old days.
Source Paridhi
Dark blue concrete wall with some small dust spots.
Source Atle Mo
Zero CC tileable dry grass texture, photographed and made by me. CC0
Source Sojan Janso
Prismatic Groovy Concentric Background
Source GDJ
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
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
Here's a new gray "fabric" pattern. Use it as backgrounds for websites or for other purposes.
Source V. Hartikainen