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
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Little x’es, noise and all the stuff you like. Dark like a Monday, with a hint of blue.
Source Tom McArdle
One week and it's Easter already. Thought I would revisit the decorated egg contest at inkscape community: http://forum.inkscapecommunity.com/index.php?topic=118.0
Source Lazur URH
Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
Prismatic Geometric Pattern Variation 2 With Background
Source GDJ
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
Black And White Floral Pattern Background Inverse
Source GDJ
A seamless pattern formed from cross 4. To get the original tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin