A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
You know you love wood patterns, so here’s one more.
Source Richard Tabor
Prismatic Groovy Concentric Background No Black
Source GDJ
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
White circles connecting on a light gray background.
Source Mark Collins
A version without colours blended together to give a different look.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A comeback for you: the popular Escheresque, now in black.
Source Patten
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
"Beige Stone", Tileable Texture.
Source V. Hartikainen
Prismatic Geometric Pattern Background 2
Source GDJ
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
An alternative colour scheme to the original seamless pattern.
Source Firkin
From a drawing in 'Codogno e il suo territorio nella cronaca e nella storia'', Gio and Giarella Cairo, 1897.
Source Firkin
Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin