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
Inspired by a drawing in 'Poems', James Smith, 1881.
Source Firkin
Zero CC tileable grass texture, photographed and made by me. CC0
Source Sojan Janso
An alternative colour scheme to the original seamless pattern.
Source Firkin
A seamless design of flowers remixed from a jpg on Pixabay by Prawny.
Source Firkin
Looks like an old rug or a computer chip.
Source Patutin Sergey
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
From drawing in 'Musings in Maoriland', Thomas Bracken, 1890.
Source Firkin
A seamless pattern of "sewn stripes" colored in light gray.
Source V. Hartikainen
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
Carbon fiber is never out of fashion, so here is one more style for you.
Source Alfred Lee
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
Remixed from an image on Pixabay uploaded by Prawny
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin