From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
No idea what Nistri means, but it’s a crisp little pattern nonetheless.
Source Markus Reiter
Colored maple leaves scattered on a surface. This is tileable, so it can be used as a background or wallpaper.
Source Eady
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
A bit strange this one, but nice at the same time.
Source Diogo Silva
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
From a drawing in 'Worsborough; its historical associations and rural attractions', Joseph Wilkinson, 1879.
Source Firkin
Vector version of a JPG that was uploaded to Pixabay by theasad121
Source Firkin
A seamless texture of a rough concrete surface.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
Light gray paper pattern with small traces of fiber and some dust.
Source Atle Mo
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin