Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
The name is totally random, but hey, it sounds good.
Source Atle Mo
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
One more brick pattern. A bit more depth to this one.
Source Benjamin Ward
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Fix and cc0 to get the tile this is based on.
Source SliverKnight
Inspired by a 1930s wallpaper pattern I saw on TV.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
This ladies and gentlemen, is texturetastic! Love it.
Source Adam Pickering
Derived from an image that was uploaded to Pixabay by starchim01
Source Firkin
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Can never have too many knitting patterns, especially as nice as this.
Source Victoria Spahn
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
Square design drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
A heavy hitter at 400x400px, but lovely still.
Source Breezi
Prismatic Abstract Line Art Pattern Background
Source GDJ
From a drawing of the coat of arms of the Ottoman Empire on Wikimedia.
Source Firkin
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
To get the tile this is based on, 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
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
A background tile of dark textile. Made this a long time ago and just now decided to publish it.
Source V. Hartikainen