Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
From a drawing in 'Royal Ramsgate', James Simson, 1897.
Source Firkin
A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
The image depicts a seamless pattern made using a bird's face.
Source Yamachem
Black & white version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
This one could be the shirt of a golf player. Angled lines in different thicknesses.
Source Olivier Pineda
By popular request, an outline version of the pentagon pattern.
Source Atle Mo
There are many carbon patterns, but this one is tiny.
Source Designova
One more brick pattern. A bit more depth to this one.
Source Benjamin Ward
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
A blue gray fabric-like texture for websites. An yet another fabric-like texture. It has subtle vertical and diagonal stripes to it.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Colour version of the original pattern.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A beautiful dark wood pattern, superbly tiled.
Source Omar Alvarado
The 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 'Uit de geschiedenis der Heilige Stede te Amsterdam', Yohannes Sterck, 1898.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein