Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Dark blue concrete wall with some small dust spots.
Source Atle Mo
Geometric triangles seem to be quite hot these days.
Source Pixeden
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Psychedelic Geometric Background No Black
Source GDJ
A seamless texture of a rough concrete surface.
Source V. Hartikainen
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
Geometric lines are always hot, and this pattern is no exception.
Source Listvetra
Gold Triangular Seamless Pattern No Background
Source GDJ
A simple but elegant classic. Every collection needs one of these.
Source Christopher Burton
Tile available in Inkscape using shift-alt-i on the selected rectangle
Source Firkin
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin