I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Alternative colour scheme for the original floral pattern.
Source Firkin
Seamless Prismatic Geometric Pattern With Background
Source GDJ
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
From a drawing in 'Uit de geschiedenis der Heilige Stede te Amsterdam', Yohannes Sterck, 1898.
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
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien
Colourful background achieved with gradient fills.
Source Firkin
Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
The original enhanced with one of Inkscapes's filters.
Source Firkin
The tile this is based on was adapted from an image that was uploaded to Pixabay by frolicsomepl. It can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
Same as gray sand but lighter. A sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk