A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
Used in small doses, this could be a nice subtle pattern. Used on a large surface, it’s dirty!
Source Paul Reulat
A dark denim looking pattern. 145×145 pixels.
Source Atle Mo
Prismatic Groovy Concentric Background 4 No Black
Source GDJ
Repeating squares overlapping.
Source Pete Fecteau
Sometimes you just need the simplest thing.
Source Fabricio
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Prismatic Geometric Pattern Background 2
Source GDJ
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
From a drawing in 'Worsborough; its historical associations and rural attractions', Joseph Wilkinson, 1879.
Source Firkin
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
A comeback for you: the popular Escheresque, now in black.
Source Patten
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
Prismatic Hexagonalist Pattern No Background
Source GDJ
Background pattern originally a PNG drawn in Paint.net
Source Firkin
Zero CC Mossy stone tileable texture, photographed and made by me. CC0
Source Sojan Janso
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers