I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
A white version of the very popular linen pattern.
Source Ant Ekşiler
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Zero CC tileable dry grass texture, photographed and made by me. CC0
Source Sojan Janso
Stefan is hard at work, this time with a funky pattern of squares.
Source Stefan Aleksić
ZeroCC tileable stone texture, edited from pixabay. CC0
Source Sojan Janso
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Prismatic Geometric Pattern Variation 2 With Background
Source GDJ
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
This one is something special. I’d call it a flat pattern, too. Very well done, sir!
Source GetDiscount
A seamless pattern with a unit cell drawn as a bitmap in Paint.net and vectorized in Vector Magic.
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
I have no idea what J Boo means by this name, but hey – it’s hot.
Source j Boo
Formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
Seamless pattern inspired by a drawing on Pixabay. To get the tile this is formed from, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Fix and cc0 to get the tile this is based on.
Source SliverKnight