This is so subtle you need to bring your magnifier!
Source Carlos Valdez
A bit of scratched up grayness. Always good.
Source Dmitry
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
A bit like some carbon, or knitted netting if you will.
Source Anna Litvinuk
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Retro Circles Background 5 No Black
Source GDJ
From a drawing in 'Picturesque New Guinea', J Lindt, 1887.
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
Feel free to download and use it, or see the rest of the dark background patterns that I have made. Anyway, I hope you will find something that you like.
Source V. Hartikainen
Just the symbols of the signs of the zodiac distributed in a chequer board-like pattern
Source Firkin
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
A grayscale fabric pattern with vertical lines of stitch holes.
Source V. Hartikainen
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
Here's a repeatable texture that resembles a light green concrete wall or something similar.
Source V. Hartikainen
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
No idea what Nistri means, but it’s a crisp little pattern nonetheless.
Source Markus Reiter
Zero CC tileable moss or lichen covered stone texture, edited from pixabay. CC0
Source Sojan Janso
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin