People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
Remixed from a JPG that was uploaded to Pixabay by theasad121
Source Firkin
Medium gray pattern with small strokes to give a weave effect.
Source Catherine
Geometric lines are always hot, and this pattern is no exception.
Source Listvetra
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Colour version of the original pattern.
Source Firkin
Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
A pattern drawn in Paint.net and vectorized in Inkscape.
Source Firkin
This is lovely, just the right amount of subtle noise, lines and textures.
Source Richard Tabor
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Seamless Dark Grunge Texture. Here's a new grunge texture for use as a background.
Source V. Hartikainen
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin