A seamless gray background texture suitable for use on websites. To me, it has the look of stone. Feel free to modify it to meet your needs (by making it a bit lighter or darker, for example).
Source V. Hartikainen
It’s big, it’s gradient—and it’s square.
Source Brankic1979
Stefan is hard at work, this time with a funky pattern of squares.
Source Stefan Aleksić
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Dark and hard, just the way we like it. Embossed triangles makes a nice pattern.
Source Ivan Ginev
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
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
I have no idea how to describe this one, but it’s light and delicate.
Source JBasoo
Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo
A beautiful dark wood pattern, superbly tiled.
Source Omar Alvarado
A free tileable background colored in off-white (antique white) color.
Source V. Hartikainen
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Retro Circles Background 8 No Black
Source GDJ
A seamless pattern formed from a square tile based on a jpg on Pixabay. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
You were craving more leather, so I whipped this up by scanning a leather jacket.
Source Atle Mo
The image depicts meshed silhouettes of various things.The original image is an OCAL clipart called "Enter FOSSASIA 2016 #IoT T-shirt Design Contest" uploaded by "openclipart".Thanks.
Source Yamachem
A version without colours blended together to give a different look.
Source Firkin
Prismatic Polka Dots Mark II No Background
Source GDJ
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin