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
A seamless pattern formed from a tile made from page ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Hexagonalist Pattern No Background
Source GDJ
There are many carbon patterns, but this one is tiny.
Source Designova
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
From a drawing in 'Handbook of the excursions proposed to be made by the Lincoln Diocesan Architectural Society, on the 27th and 28th of May, 1857', Edward Trollope, 1857.
Source Firkin
Prismatic Polka Dots 3 No Background
Source GDJ
Alternative colour scheme for the original floral pattern.
Source Firkin
A light gray background pattern with seamless fabric-like texture and almost unnoticeable stripes.
Source V. Hartikainen
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
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
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
Real snow that tiles, not easy. This is not perfect, but an attempt.
Source Atle Mo
Zero CC tileable Laminate wood texture, photographed and made by me. CC0
Source Sojan Janso
No, not the band but the pattern. Simple squares in gray tones, of course.
Source Atle Mo
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective