The base gradient edited so now more details are rendered.
Source Lazur URH
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
Prismatic Abstract Line Art Pattern Background
Source GDJ
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
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 pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A dark striped seamless pattern suitable for use as a background on websites.
Source V. Hartikainen
Subtle scratches on a light gray background.
Source Andrey Ovcharov
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
This seamless pattern consists of a blue grid on a yellow background.
Source V. Hartikainen
Remixed from a PNG that was uploaded to Pixabay by k_jprather
Source Firkin
It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
The image depicts an edo-era pattern called "same-komon" or "鮫小紋"which looks like a shark skin.The "same" in Japanese means shark in English.
Source Yamachem
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective