From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A free seamless background texture that looks like a brown stone wall.
Source V. Hartikainen
An abstract Background pattern of purple twisty patterns.
Source TikiGiki
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Classic vertical lines, in all its subtlety.
Source Cody L
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo
Prismatic Geometric Tessellation Pattern 2 No Background
Source GDJ
A pale olive green background with a seamless texture.
Source V. Hartikainen
Remixed from a drawing in 'Prehistoric Man: researches into the origin of civilisation in the old and the new world', Daniel Wilson, 1876.
Source Firkin
A free background pattern with abstract green tiles.
Source V. Hartikainen
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 pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ