A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Prismatic Groovy Concentric Background
Source GDJ
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
Washi (和紙?) is a type of paper made in Japan. Here’s the pattern for you!
Source Carolynne
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
Psychedelic Geometric Background No Black
Source GDJ
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
Formed by distorting the inside front cover of 'Diversæ insectarum volatilium : icones ad vivum accuratissmè depictæ per celeberrimum pictorem', Jacob Hoefnagel, 1630.
Source Firkin
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
A pattern derived from repeating unit cells each derived from part of a mosaic in paint.net. The starting point for the mosaic was a picture of some prawns!
Source Firkin
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
A bit like some carbon, or knitted netting if you will.
Source Anna Litvinuk
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
A textured blue background pattern with vertical stripes.
Source V. Hartikainen
Black brick wall pattern. Brick your site up!
Source Alex Parker
Here's a repeatable texture that resembles a light green concrete wall or something similar.
Source V. Hartikainen
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
Sharp but soft triangles in light shades of gray.
Source Pixeden
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat
A free repetitive background with a dark concrete wall like texture. This one may be used in dark web site designs.
Source V. Hartikainen
Farmer could be some sort of fabric pattern, with a hint of green.
Source Fabian Schultz
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
A seamless texture of a rough concrete surface.
Source V. Hartikainen