The image depicts a seamless pattern of Japanese Edo pattern called "kikkou-matsu" or "亀甲松" meaning " tortoiseshell-pinetree".The real pinetree is like this: https://jp.pinterest.com/pin/500744052301065077/
Source Yamachem
A seamless pattern the starting point for which was a 'light rays' rendering in Paint.net.
Source Firkin
Honestly, who does not like a little pipe and mustache?
Source Luca Errico
It was called Navy Blue, but I made it dark. You know, the way I like it.
Source Ethan Hamilton
Abstract Ellipses Background Grayscale
Source GDJ
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Wild Oliva or Oliva Wilde? Darker than the others, sort of a medium dark pattern.
Source Badhon Ebrahim
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
By popular request, an outline version of the pentagon pattern.
Source Atle Mo
A nice and simple gray stucco material. Great on its own, or as a base for a new pattern.
Source Bartosz Kaszubowski
Here's a dark background pattern that contains a steel grid pattern as a texture. Use it as a website background or for other purposes. It's free!
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Utilising a bird from s-light and some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
The original has been presented as black on transparent and stored in the pattern definitions. To retrieve the unit tile select the rectangle in Inkscape and use shift+alt+i
Source Firkin
This could be a hippy vintage wallpaper.
Source Tileable Patterns
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
CC0 and seamless wellington boot pattern.
Source SliverKnight
Prismatic Groovy Concentric Background 4
Source GDJ