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
Just what the name says, paper fibers. Always good to have.
Source Heliodor jalba
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
The tile can be had by selecting the rectangle in Inkscape and using shift+alt+i. Remixed from a drawing in 'Flowers of Song', Frederick Weatherly, 1895.
Source Firkin
Remixed from a drawing in 'Очерки Русской Исторіи въ памятникахъ быта', Petr Polevoi, 1879.
Source Firkin
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
A bit strange this one, but nice at the same time.
Source Diogo Silva
Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo
I’m starting to think I have a concrete wall fetish.
Source Atle Mo
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
The image depicts a seamless pattern of Japanese Edo pattern called "kikkou-matsu" or "亀甲松" meaning " tortoiseshell-pinetree".The real pinetree is like this: https://jp.pinterest.com/pin/500744052301065077/
Source Yamachem
Lovely pattern with splattered vintage speckles.
Source David Pomfret
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
There are many carbon patterns, but this one is tiny.
Source Designova
More in the paper realm, this time with fibers.
Source Jorge Fuentes
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
Thin lines, noise and texture creates this crisp dark denim pattern.
Source Marco Slooten
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett