The image depicts a seamless pattern of pine tree leaves.
Source Yamachem
From an image on opengameart.org shared by rubberduck.
Source Firkin
A slightly grainy paper pattern with small horizontal and vertical strokes.
Source Atle Mo
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
A colourful background drawn originally in paint.net and vectorised in Vector Magic.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
ZeroCC tileable mossy (lichen) stone texture, edited from pixabay. CC0
Source Sojan Janso
Just a nice looking textured pattern with faded blue stripes. Well, that's it for today... one background a day, as usual.
Source V. Hartikainen
No relation to the band, but damn it’s subtle!
Source Thomas Myrman
Formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
ZeroCC tileable wood boards texture, photographed and made by me. CC0
Source Sojan Janso
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
Zero CC tileable hard cover red book, scanned and made by me. CC0
Source Sojan Janso
One more brick pattern. A bit more depth to this one.
Source Benjamin Ward
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Zero CC tileable hard cover cells book texture, 4k, scanned and made by me. CC0
Source Sojan Janso
Scanned some rice paper and tiled it up for you. Enjoy.
Source Atle Mo
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
One more sharp little tile for you. Subtle circles this time.
Source Blunia
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
If you’re sick of the fancy 3D, grunge and noisy patterns, take a look at this flat 2D brick wall.
Source Listvetra
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida