Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Prismatic Hexagonalism Pattern No Background
Source GDJ
A seamless pattern the unit cell for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A seamless texture of a rough concrete surface.
Source V. Hartikainen
8 by 8 pixels, and just what the title says.
Source pixilated
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
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
A seamless texture of black leather. I think it will look best when used in headers, footers or sidebars.
Source V. Hartikainen
This is the remix of an Openclipart clipart called "Maze" uploaded by "any_ono_mous".Thanks.This is a seamless pattern of a maze.
Source Yamachem
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A seamless pattern of "sewn stripes" colored in light gray.
Source V. Hartikainen
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
A pale yellow background pattern with vertical stripes. The stripes are partially faded. I think this background image turned out pretty well, especially those faded stripes.
Source V. Hartikainen
A repeating background of beige paper with vintage look. Repeats to infinity, as usual.
Source V. Hartikainen
The tile for this is based on a repeating unit close to a design on Pixabay. It can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Abstract Tiled Background Extended 8
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Remixed from a raster on Pixabay, that was uploaded by ArtsyBee.
Source Firkin
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
A web texture of brown canvas. Will look great, when used in dark web designs.
Source V. Hartikainen
Utilising a bird from s-light and some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin