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
This makes me wanna shoot some pool! Sweet green pool table pattern.
Source Caveman
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
The edges of all the red objects line up either vertically or horizontally, but it doesn't appear so. Made from a square tile that can be got by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Number five from the same submitter, makes my job easy.
Source Dima Shiper
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin