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 drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
A seamless web texture with illustration of pale color stains on canvas.
Source V. Hartikainen
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
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Another fairly simple design drawn in Paint.net and vectorized in Inkscape.
Source Firkin
Have you wondered about how it feels to be buried alive? Here is the pattern for it.
Source Hendrik Lammers
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
An orange vertically striped background pattern. Feel free to download and use this orange background pattern, for example, on the web). It resembles a wallpaper with vertical stripes or something similar to it.
Source V. Hartikainen
Retro Circles Background 8 No Black
Source GDJ
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo
Looks like a technical drawing board: small squares forming a nice grid.
Source We Are Pixel8
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
From a drawing in 'Picturesque New Guinea', J Lindt, 1887.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A nice and simple white rotated tile pattern.
Source Another One
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin