Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
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
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
Prismatic Hexagonalism Pattern No Background
Source GDJ
From a drawing in 'Picturesque New Guinea', J Lindt, 1887.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
Black brick wall pattern. Brick your site up!
Source Alex Parker
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Prismatic Abstract Geometric Background 3
Source GDJ
Formed by distorting a JPG from PublicDomainPictures
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
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein