A comeback for you: the popular Escheresque, now in black.
Source Patten
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
Imagine you zoomed in 1000X on some fabric. But then it turned out to be a skeleton!
Source Angelica
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
Not the Rebel alliance, but a dark textured pattern.
Source Hendrik Lammers
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
This background has abstract texture with some similarities to wood.
Source V. Hartikainen
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Prismatic Geometric Pattern Background
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors
A free seamless texture of reptile skin colored in a dark brown color. As always, you may use it as a repeated background image in your web design works, or for any other purposes.
Source V. Hartikainen
Tweed is back in style – you heard it here first. Also, the @2X version here is great!
Source Simon Leo
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks.
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using 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
You know you can’t get enough of these linen-fabric-y patterns.
Source James Basoo
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin