A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
Prismatic Groovy Concentric Background 3
Source GDJ
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
Prismatic Polka Dots Mark II No Background
Source GDJ
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
The tile this fill pattern is based on can be had by using shift+alt+i on the rectangle.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
A background pattern with blue on white vertical stripes.
Source V. Hartikainen
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov