Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Adapted from an image that was uploaded to Pixabay by Anerma.
Source Firkin
Prismatic Groovy Concentric Background
Source GDJ
A free green background pattern with a pattern of rhombuses on a seamless texture. Feel free to use it as a tiled background image on your web site.
Source V. Hartikainen
This background has abstract texture with some similarities to wood.
Source V. Hartikainen
A seamless pattern with wide vertical stripes colored in pale yellow.
Source V. Hartikainen
From a drawing in 'Az Osztrák-Magyar Monarchia irásban és képben', 1885.
Source Firkin
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors
You were craving more leather, so I whipped this up by scanning a leather jacket.
Source Atle Mo
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
Prismatic Groovy Concentric Background 2
Source GDJ
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
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
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
A seamless striped fabric-like texture colored in a dark reddish brown color.
Source V. Hartikainen
On a large canvas you can see it tiling, but used on smaller areas, it’s beautiful.
Source Paul Phönixweiß
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
This one needs to be used in small areas; you can see it repeat.
Source Luca
Pixel by pixel, sharp and clean. Very light pattern with clear lines.
Source M.Ashok
A free background pattern with abstract green tiles.
Source V. Hartikainen