People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
A bit of scratched up grayness. Always good.
Source Dmitry
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Prismatic Polyskelion Pattern No Background
Source GDJ
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
The image depicts the Japanese Edo pattern called "seigaiha" or "青海波" meaning "blue -sea- wave".I hope it's suitable for the summer season.
Source Yamachem
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
Background Wall, Art Abstract, Watercolor Vintage style CC0 texture.
Source Ractapopulous
This beige background pattern resembles a concrete wall with engravings or something similar to it.
Source V. Hartikainen
Greyscale version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Inspired by a JPG that was uploaded to Pixabay by kokon_art
Source Firkin
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
Retro Circles Background 5 No Black
Source GDJ
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
More leather, and this time it’s bigger! You know, in case you need that.
Source Elemis
Prismatic Hexagonalism Pattern No Background
Source GDJ
Sharp pixel pattern, just like the good old days.
Source Paridhi
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin