Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo
A pattern drawn in Paint.net and vectorized in Inkscape.
Source Firkin
A seamless web texture of "green stone".
Source V. Hartikainen
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
This one is amazing, truly original. Go use it!
Source Viahorizon
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
Prismatic Groovy Concentric Background 3
Source GDJ
To get the tile this is made up from select the rectangle in Inkscape and use shift+alt+i.
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
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
Some dark 45 degree angles creating a nice pattern. Huge.
Source Dark Sharp Edges
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab