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
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
People seem to enjoy dark patterns, so here is one with some circles.
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
Embossed lines and squares with subtle highlights.
Source Alex Parker
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Black brick wall pattern. Brick your site up!
Source Alex Parker
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A pale olive green background with a seamless texture.
Source V. Hartikainen
The original enhanced with some gradients.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
An abstract web texture of a polished blue stone (or does it look more like ice).
Source V. Hartikainen
Fix side and a seamless pattern formed from circles.
Source SliverKnight
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
From a drawing in 'An Old Maid's Love. A Dutch tale told in English', Maarten Maartens, 1891.
Source Firkin
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
A beautiful dark padded pattern, like an old classic sofa.
Source Chris Baldie
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
With a name like this, it has to be hot. Diagonal lines in light shades.
Source Isaac