One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
More Japanese-inspired patterns, Gold Scales this time.
Source Josh Green
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
There are many carbon patterns, but this one is tiny.
Source Designova
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
Zero CC tileable dry grass texture, photographed and made by me. CC0
Source Sojan Janso
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Prismatic Polka Dots 3 No Background
Source GDJ
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
Just like the black maze, only in light gray. Duh.
Source Peax
Tiny little flowers growing on your screen. Nice, huh?
Source Themes Tube
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
Prismatic Abstract Geometric Background 3
Source GDJ
Feel free to download this "Dark Wood" background texture for your web site. The background tiles seamlessly!
Source V. Hartikainen
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
A seamless marble-like texture colored in light blue.
Source V. Hartikainen