Seamless pattern the basic tile for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
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
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Adapted from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Prismatic Basic Pattern 2 No Background
Source GDJ
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
This is a remix of "blue wave-seigaiha".I hope this subtle color version of Seigaiha would be suitable for background .
Source Yamachem
Zero CC tileable brick texture, photographed and made by me. CC0
Source Sojan Janso
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Derived from an image that was uploaded to Pixabay by TheDigitalArtist
Source Firkin
Washi (和紙?) is a type of paper made in Japan. Here’s the pattern for you!
Source Carolynne
You could get a bit dizzy from this one, but it might come in handy.
Source Dertig Media
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo