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
Used a cherry by doctormo to make this seamless pattern
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
From a drawing in 'From Snowdon to the Sea. Striking stories of North and South Wales', Marie Trevelyan, 1895.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
You know you can’t get enough of these linen-fabric-y patterns.
Source James Basoo
A version without colours blended together to give a different look.
Source Firkin
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
Colourful background achieved with gradient fills.
Source Firkin
A textured blue background pattern with vertical stripes.
Source V. Hartikainen
Geometric triangles seem to be quite hot these days.
Source Pixeden
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Your eyes can trip a bit from looking at this – use it wisely.
Source Michal Chovanec
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
ZeroCC tileabel stone granite texture, edited from pixabay. CC0
Source Sojan Janso
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Tiny circle waves, almost like the ocean.
Source Sagive
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Thin lines, noise and texture creates this crisp dark denim pattern.
Source Marco Slooten
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