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
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
Here is a new seamless wood texture for using as blog or website backgrounds.
Source V. Hartikainen
Light and tiny, just the way you like it.
Source Rohit Arun Rao
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
Remixed from a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Brushed aluminum, in a bright gray version. Lovely 2X as well.
Source Andre Schouten
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
Wasn't satisfied with the original's colouring. Too much component transfer and colormatrixes yet the results are lacking a bit. So this time it is a simple black to transparent fade, making it possible remixing easily once there will be other blending modes supported as well. Probably in inkscape 0.92.
Source Lazur URH
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
From a drawing in 'Hundert Jahre in Wort und Bild', S. Stefan, 1899.
Source Firkin
This is the remix of "plant pattern 02".I changed the object color to white and the BG to purple.The image a seamless pattern derived from a weed which I can't identify.The original weed image is from here:jp.pinterest.com/pin/500744052301423641/
Source Yamachem
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
A pattern derived from repeating unit cells each derived from part of a mosaic in paint.net. The starting point for the mosaic was a picture of some prawns!
Source Firkin
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua