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
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
As simple and subtle as it gets. But sometimes that’s just what you want.
Source Designova
Not the Rebel alliance, but a dark textured pattern.
Source Hendrik Lammers
A nice and simple gray stucco material. Great on its own, or as a base for a new pattern.
Source Bartosz Kaszubowski
Scanned some rice paper and tiled it up for you. Enjoy.
Source Atle Mo
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
Prismatic Polka Dots 3 No Background
Source GDJ
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Prismatic Basic Pattern 2 No Background
Source GDJ
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
A repeating background with seamless texture of stone. There haven't been any stone-like backgrounds for a while, so I have decided to create one more. The rest can be found in the appropriate category.
Source V. Hartikainen
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A free grid paper background pattern for using on web sites.
Source V. Hartikainen
A web texture of brown canvas. Will look great, when used in dark web designs.
Source V. Hartikainen
Pattern Background, Texture, Photoshop Structure style CC0 texture.
Source Darkmoon1968
You were craving more leather, so I whipped this up by scanning a leather jacket.
Source Atle Mo
More tactile goodness. This time in the form of some rough cloth.
Source Bartosz Kaszubowski
You know, tiny and sharp. I’m sure you’ll find a use for it.
Source Atle Mo
I’m guessing this is related to the Sony Vaio? It’s a nice pattern no matter where it’s from.
Source Zigzain