Tile available in Inkscape using shift-alt-i on the selected rectangle
Source Firkin
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Light gray version of the Binding pattern that looks a bit like fabric.
Source Newbury
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
This background has abstract texture with some similarities to wood.
Source V. Hartikainen
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
A bit of scratched up grayness. Always good.
Source Dmitry
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Prismatic Polka Dots Mark II No Background
Source GDJ
The following orange background pattern resembles a honeycomb.
Source V. Hartikainen
Prismatic Chevrons Pattern 5 With Background
Source GDJ
Colour version of the original seamless pattern.
Source Firkin
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
Here's a subtle marble-like background for use on websites.
Source V. Hartikainen