Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
Prismatic Geometric Tessellation Pattern 3 No Background
Source GDJ
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Alternative colour scheme. 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
Same as Silver Scales, but in black. Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Orange-red pattern for tiled backgrounds.
Source V. Hartikainen
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
Super detailed 16×16 tile that forms a beautiful pattern of straws.
Source Pavel
Prismatic Abstract Geometric Background 4
Source GDJ
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
A nice looking light gray background pattern with diagonal stripes.
Source V. Hartikainen
A classic dark tile for a bit of vintage darkness.
Source Listvetra
Green Background Pattern
Source V. Hartikainen
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
A seamless tessellation pattern. To get the tile this is formed from, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez