People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
No relation to the band, but damn it’s subtle!
Source Thomas Myrman
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
Light gray version of the Binding pattern that looks a bit like fabric.
Source Newbury
Colour version of the original pattern inspired by the front cover of 'Old and New Paris', Henry Edwards, 1894.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Prismatic Groovy Concentric Background 4
Source GDJ
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
Prismatic Abstract Geometric Background 5
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
Prismatic Groovy Concentric Background 5
Source GDJ
White circles connecting on a light gray background.
Source Mark Collins
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks. https://cloaks.deviantart.com
Source Atle Mo
A pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
From a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
A seamless pattern formed from a modified version of rwwgub's tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The file was named striped lens, but hey – Translucent Fibres works too.
Source Angelica