Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
Alternative colour scheme for the original floral pattern.
Source Firkin
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
From a drawing in 'Hyde Park from Domesday-Book to date', John Ashton, 1896.
Source Firkin
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
ZeroCC tileable wood boards texture, photographed and made by me. CC0
Source Sojan Janso
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
Nothing like a clean set of bed sheets, huh?
Source Badhon Ebrahim
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
Remixed from a drawing that was uploaded to Pixabay by DavidZydd
Source Firkin
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
The tile can be had by using shift+alt+i on the selected rectangle in Inkscape
Source Firkin
Not the most creative name, but it’s a good all-purpose light background.
Source Dmitry