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
A large (588x375px) sand-colored pattern for your ever-growing collection. Shrink at will.
Source Alex Tapein
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
This ladies and gentlemen, is texturetastic! Love it.
Source Adam Pickering
A pattern drawn in Paint.net and vectorized in Inkscape.
Source Firkin
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo
Hey, you never know when you’ll need a bird pattern, right?
Source Pete Fecteau
A brown metallic grid pattern layered on top of a dark fabric texture. It should look great when using as a tiled background on web pages, especially blogs.
Source V. Hartikainen
This one needs to be used in small areas; you can see it repeat.
Source Luca
This background pattern has futuristic look. So, maybe it could be used on websites or blogs dedicated to video games?!
Source V. Hartikainen
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin