A free repetitive background with a dark concrete wall like texture. This one may be used in dark web site designs.
Source V. Hartikainen
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I. A version of the original with random colors.
Source Firkin
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Just like the black maze, only in light gray. Duh.
Source Peax
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
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
A seamless background texture of old cardboard.
Source V. Hartikainen
This one has rusty dark brown texture.
Source V. Hartikainen
Looks like an old wall. I guess that’s it then?
Source Viahorizon
Sharp pixel pattern, just like the good old days.
Source Paridhi