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
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
A beautiful dark padded pattern, like an old classic sofa.
Source Chris Baldie
This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
Sort of reminds me of those old house wallpapers.
Source Tish
This is the remix of "Background pattern 115" uploaded by "Firkin".Thanks.
Source Yamachem
Geometric triangles seem to be quite hot these days.
Source Pixeden
Green Background Pattern
Source V. Hartikainen
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
This makes me wanna shoot some pool! Sweet green pool table pattern.
Source Caveman
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
You just can’t get enough of the fabric patterns, so here is one more for your collection.
Source Krisp Designs
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
Orange-red pattern for tiled backgrounds.
Source V. Hartikainen
Remixed from a PNG that was uploaded to Pixabay by k_jprather
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Heavily remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin