People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
I have no idea how to describe this one, but it’s light and delicate.
Source JBasoo
A seamless light gray paper texture with horizontal double lines.
Source V. Hartikainen
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
This is the remix of "polka dot seamless pattern".The image depicts polka dot seamless pattern.
Source Yamachem
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
8 by 8 pixels, and just what the title says.
Source pixilated
Washi (和紙?) is a type of paper made in Japan. Here’s the pattern for you!
Source Carolynne
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
Vector version of a JPG that was uploaded to Pixabay by theasad121
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i
Source Firkin
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Inspired by a design found in 'Konstantinápolyi emlékeim', Miklos Chriszto, 1893.
Source Firkin
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin