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
Sort of like the back of a wooden board. Light, subtle, and stylish, just the way we like it!
Source Nikolalek
A seamless pattern made from the gold Penrose triangle by GDJ and the two remixes
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
From a drawing in 'Bond Slaves. The story of a struggle.', Isabella Varley, 1893.
Source Firkin
Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo
A seamless pattern formed from a modified version of rwwgub's tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A re-make of the Gradient Squares pattern.
Source Dimitar Karaytchev
The original enhanced with some gradients.
Source Firkin
Prismatic Abstract Geometric Background derived from an image on Pixabay.
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
From a drawing in 'Codogno e il suo territorio nella cronaca e nella storia'', Gio and Giarella Cairo, 1897.
Source Firkin
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
Remixed from a drawing in 'A Girl in Ten Thousand', Elizabeth Meade, 1896.
Source Firkin
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
A seamless pattern formed from cross 4. To get the original tile 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
Inspired by a drawing seen in 'City of Liverpool', James Picton, 1883.
Source Firkin
Luxurious looking pattern (for a T-shirt maybe?) with a hint of green.
Source Simon Meek
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin