Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Just like the black maze, only in light gray. Duh.
Source Peax
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss
Zero CC Mossy stone tileable texture, photographed and made by me. CC0
Source Sojan Janso
I have no idea what J Boo means by this name, but hey – it’s hot.
Source j Boo
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
Sort of like the back of a wooden board. Light, subtle, and stylish, just the way we like it!
Source Nikolalek
Little x’es, noise and all the stuff you like. Dark like a Monday, with a hint of blue.
Source Tom McArdle
You guessed it – looks a bit like cloth.
Source Peax Webdesign
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
8 by 8 pixels, and just what the title says.
Source pixilated
Small dots with minor circles spread across to form a nice mosaic.
Source John Burks
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A seamless background pattern of dark brown wood planks.
Source V. Hartikainen
Prismatic Abstract Background Design
Source GDJ
A repeating background with wood/straw like texture.
Source V. Hartikainen
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A repeating background of beige (or is it more vanilla yellow) textured stripes. One more background with stripes.
Source V. Hartikainen