Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo
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
Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin
From a drawing in 'Two Women in the Klondike', Mary Hitchcock, 1899.
Source Firkin
A free seamless texture of reptile skin colored in a dark brown color. As always, you may use it as a repeated background image in your web design works, or for any other purposes.
Source V. Hartikainen
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo
Just what the name says, paper fibers. Always good to have.
Source Heliodor jalba
A textured blue background pattern with vertical stripes.
Source V. Hartikainen
A seamless pattern made from the gold Penrose triangle by GDJ and the two remixes
Source Firkin