Here's a dark background pattern that contains a steel grid pattern as a texture. Use it as a website background or for other purposes. It's free!
Source V. Hartikainen
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
Almost like little fish shells, or dragon skin.
Source Graphiste
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
ZeroCC tileable wood boards texture, photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
One more updated pattern. Not really carbon fiber, but it’s the most popular pattern, so I’ll give you an extra choice.
Source Atle Mo
Seamless pattern formed from a tile that can be had 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
A chequerboard pattern with a fruit theme. The fruits are from a posting by inkscapeforum.it.
Source Firkin
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
Geometric lines are always hot, and this pattern is no exception.
Source Listvetra
A free green background pattern with a pattern of rhombuses on a seamless texture. Feel free to use it as a tiled background image on your web site.
Source V. Hartikainen
A browner version of the original weathered fence texture.
Source Firkin
From a drawing in 'From Snowdon to the Sea. Striking stories of North and South Wales', Marie Trevelyan, 1895.
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
Not the Rebel alliance, but a dark textured pattern.
Source Hendrik Lammers
Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Everyone needs some stardust. Sprinkle it on your next project.
Source Atle Mo
A seamless web texture of "green stone".
Source V. Hartikainen
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić