A pale olive green background with a seamless texture.
Source V. Hartikainen
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Prismatic Abstract Geometric Background derived from an image on Pixabay.
Source GDJ
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
Can never have too many knitting patterns, especially as nice as this.
Source Victoria Spahn
Prismatic Abstract Geometric Background 5
Source GDJ
You guessed it – looks a bit like cloth.
Source Peax Webdesign
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
Stefan is hard at work, this time with a funky pattern of squares.
Source Stefan Aleksić
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Here's a bluish gray striped background pattern for use on web sites.
Source V. Hartikainen
The classic notebook paper with horizontal stripes.
Source Are Sundnes
This texture looks like old leather. It should look great as a background on web pages.
Source V. Hartikainen
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Sharp but soft triangles in light shades of gray.
Source Pixeden
Remixed from an image on Pixabay, the original having been uploaded by darkmoon1968.
Source Firkin
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin