Embossed lines and squares with subtle highlights.
Source Alex Parker
ZeroCC tileable stone texture, edited from pixabay, CC0
Source Sojan Janso
A free seamless background texture that looks like a brown stone wall.
Source V. Hartikainen
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamlessly tile-able grunge background image.
Source V. Hartikainen
Old China with a modern twist, take two.
Source Adam Charlts
A seamless pattern formed from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
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
This tiled background comes in red and consists of tiles that look like gemstones. It is more for blogs or social profiles, I think.
Source V. Hartikainen
Zero CC Mossy stone tileable texture, photographed and made by me. CC0
Source Sojan Janso
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Paper model of a tetrahedron. Modelo de papel de um tetraedro.
Source laobc
Psychedelic Geometric Background No Black
Source GDJ
Derived from a drawing in 'Historiske Afhandlinger', Adolf Jorgensen, 1898.
Source Firkin
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Remixed from an image on Pixabay, the original having been uploaded by darkmoon1968.
Source Firkin
All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
This one is amazing, truly original. Go use it!
Source Viahorizon