Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Thin lines, noise and texture creates this crisp dark denim pattern.
Source Marco Slooten
The image depicts a seamless pattern of a snow crystal.I referred to a book called ”sekka-zusetsu” or "雪華図説" which means an illustrated explanation about snow crystals.This book was published in 1832 (天保3年) or Edo period.For more about "雪華図説",see here:dl.ndl.go.jp/info:ndljp/pid/2536975
Source Yamachem
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
Psychedelic Geometric Background No Black
Source GDJ
Zero CC tileable grass texture, photographed and made by me. CC0
Source Sojan Janso
Have you wondered about how it feels to be buried alive? Here is the pattern for it.
Source Hendrik Lammers
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
This one needs to be used in small areas; you can see it repeat.
Source Luca
These dots are already worn for you, so you don’t have to.
Source Matt McDaniel
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
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
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
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Derived from a drawing in 'Elfrica. An historical romance of the twelfth century', Charlotte Boger, 1885
Source Firkin
Remixed from an image that was uploaded to Pixabay by CatherineClennan
Source Firkin
People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
Zero CC tileable hard cover red book, scanned and made by me. CC0
Source Sojan Janso
An alternative colour scheme for the original background.
Source Firkin
A blue background wallpaper for websites. It has a seamless texture with vertical stripes. It looks quite nice not only when using as a tiled background on websites, but also on computer desktops.
Source V. Hartikainen
Subtle scratches on a light gray background.
Source Andrey Ovcharov