A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
The image depicts a seamless pattern of a tortoise in tortoiseshell (hexagon).
Source Yamachem
This ons is quite old school looking. Retro, even. I like it.
Source Arno Declercq
The tile can be had by selecting the rectangle in Inkscape and using shift+alt+i. Remixed from a drawing in 'Flowers of Song', Frederick Weatherly, 1895.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
Prismatic Curved Diamond Pattern No Background
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
A comeback for you: the popular Escheresque, now in black.
Source Patten
A seamless texture of a rough concrete surface.
Source V. Hartikainen
Formed by distorting an image on Pixabay that was uploaded by gustavorezende. To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Groovy Concentric Background
Source GDJ
First pattern tailor-made for Retina, with many more to come. All the old ones are upscaled, in case you want to re-download.
Source Atle Mo
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
Not even 1kb, but very stylish. Gray thin lines.
Source Struck Axiom
Background Wall, Art Abstract, Watercolor Vintage style CC0 texture.
Source Ractapopulous
You know I’m a sucker for these. Well-crafted paper pattern.
Source Mihaela Hinayon
If you don’t like cream and pixels, you’re in the wrong place.
Source Mizanur Rahman
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin