A dark background pattern/texture of a dimpled metal plate.
Source V. Hartikainen
Prismatic Triangular Seamless Pattern III With Background
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
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
This one needs to be used in small areas; you can see it repeat.
Source Luca
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
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
Prismatic Groovy Concentric Background No Black
Source GDJ
Remixed from a PNG that was uploaded to Pixabay by VictorianLady
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Prismatic Abstract Background Design No Black
Source GDJ
Derived from an image that was uploaded to Pixabay by darkmoon1968
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen
Not the Rebel alliance, but a dark textured pattern.
Source Hendrik Lammers
An attempt for cleaning up the original image in a few steps.
Source Lazur URH
A light brushed aluminum pattern for your pleasure.
Source Tim Ward
A seamless paper background colored in pale yellow.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Prismatic Rounded Squares Grid 3 No Background
Source GDJ