You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
Might not be super subtle, but quite original in its form.
Source Alex Smith
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'Hubert Montreuil, or the Huguenot and the Dragoon', Francisca Ouvry, 1873.
Source Firkin
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
On a large canvas you can see it tiling, but used on smaller areas, it’s beautiful.
Source Paul Phönixweiß
A playful triangle pattern with different shades of gray.
Source Dimitrie Hoekstra
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
Prismatic Hypnotic Pattern No Background
Source GDJ
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
A free seamless texture of reptile skin colored in a dark brown color. As always, you may use it as a repeated background image in your web design works, or for any other purposes.
Source V. Hartikainen
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Remixed from a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
A repeating gloomy background image. This one consists of a pattern of black chains layered on top of a dark textured background.
Source V. Hartikainen
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
A free seamless background texture of "timber wall" (colored in dark brown).
Source V. Hartikainen
A seamless pattern formed from a rectangular tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
You just can’t get enough of the fabric patterns, so here is one more for your collection.
Source Krisp Designs