This is a hot one. Small, sharp and unique.
Source GraphicsWall
Inspired by the B&O Play, I had to make this pattern.
Source Atle Mo
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
Use shift+alt+i on the selected rectangle in Inkscape to get the tile this is based on
Source Firkin
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A nice and simple gray stucco material. Great on its own, or as a base for a new pattern.
Source Bartosz Kaszubowski
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
A lovely light gray pattern with stripes and a dash of noise.
Source V. Hartikainen
Remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
A pattern drawn in Paint.net and vectorized in Inkscape.
Source Firkin
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Derived from an image that was uploaded to Pixabay by mdmelo.
Source Firkin
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
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
Inspired by a drawing in 'Poems', James Smith, 1881.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
Continuing the geometric trend, here is one more.
Source Mike Warner