A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
Retro Circles Background 5 No Black
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile 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
Prismatic Chevrons Pattern 5 With Background
Source GDJ
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
Bright Multicolored Floral Background by Karen Arnold from PDP.
Source GDJ
Seamless pattern the basic tile for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Remixed from a raster on Pixabay, that was uploaded by ArtsyBee.
Source Firkin
It’s an egg, in the form of a pattern. This really is 2012.
Source Paul Phönixweiß
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
The tile can be had by selecting the rectangle in Inkscape and using shift+alt+i. Remixed from a drawing in 'Flowers of Song', Frederick Weatherly, 1895.
Source Firkin
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
Alternative colour scheme for the original floral pattern.
Source Firkin