That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
A seamlessly repeating background pattern of wood. The image is procedurally generated, and, I think, it's turned out quite well.
Source V. Hartikainen
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A seamless pattern formed from a modified version of rwwgub's tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
A tile-able background for websites with paper-like texture and a grid pattern layered on top of it.
Source V. Hartikainen
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
A light gray background pattern with seamless fabric-like texture and almost unnoticeable stripes.
Source V. Hartikainen
Same classic 45-degree pattern, dark version.
Source Luke McDonald
Imagine you zoomed in 1000X on some fabric. But then it turned out to be a skeleton!
Source Angelica
From a drawing in 'Danmarks Riges Historie af J. Steenstrup, Kr. Erslev, A. Heise, V. Mollerup, J. A. Fridericia, E. Holm, A. D. Jørgensen', 1897.
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
An abstract web texture of a polished blue stone (or does it look more like ice).
Source V. Hartikainen
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady