ZeroCC tileabel stone granite texture, edited from pixabay. CC0
Source Sojan Janso
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
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
Dark pattern with some nice diagonal stitched lines crossing over.
Source Ashton
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
The image depicts a seamless pattern of pine tree leaves.
Source Yamachem
A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
The image depicts a seamless pattern made using a bird's face.
Source Yamachem
CC0 remixed from a drawing. Walter Crane, 1914, Firkin.
Source SliverKnight
Scanned some rice paper and tiled it up for you. Enjoy.
Source Atle Mo
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
Remix from a drawing in 'Ostatnie chwile powstania styczniowego', Zygmunt Sulima, 1887.
Source Firkin
As simple and subtle as it gets. But sometimes that’s just what you want.
Source Designova
Element of beach pattern with background.
Source Rones
A seamlessly tile-able grunge background image.
Source V. Hartikainen
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Prismatic Abstract Geometric Background 4
Source GDJ
Formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin