You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
To get the repeating unit, select the rectangle in Inkscape and use shift+alt+i
Source Firkin
A browner version of the original weathered fence texture.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
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 was formed by distorting an image of a background on Pixabay.
Source Firkin
Little x’es, noise and all the stuff you like. Dark like a Monday, with a hint of blue.
Source Tom McArdle
Abstract Ellipses Background Grayscale
Source GDJ
A simple circle. That’s all it takes. This one is even transparent, for those who like that.
Source Saqib
Utilising some flowers from Almeidah. To get the unit tile, 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
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
ZeroCC tileable mossy (lichen) stone texture, edited from pixabay. CC0
Source Sojan Janso
This one is amazing, truly original. Go use it!
Source Viahorizon
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
Background formed from the original with an emboss effect
Source GDJ
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
This seamless pattern consists of a blue grid on a yellow background.
Source V. Hartikainen
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