CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
You know I love paper patterns. Here is one from Stephen. Say thank you!
Source Stephen Gilbert
Prepared mostly as a raster in Paint.net and vectorised.
Source Firkin
This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
I have no idea what J Boo means by this name, but hey – it’s hot.
Source j Boo
Prismatic Geometric Tessellation Pattern No Background
Source GDJ
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
This ladies and gentlemen, is texturetastic! Love it.
Source Adam Pickering
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Prismatic Polka Dots Mark II No Background
Source GDJ
Prismatic Abstract Geometric Background derived from an image on Pixabay.
Source GDJ
This was formed by distorting an image of a background on Pixabay.
Source Firkin
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Very simple, very blu(e). Subtle and nice.
Source Seb Jachec
Tiny shiny dots all over your screen.
Source mediumidee
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 free black metallic background pattern. Here's a new pattern I made that looks metallic.
Source V. Hartikainen
A large (588x375px) sand-colored pattern for your ever-growing collection. Shrink at will.
Source Alex Tapein
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
This one has rusty dark brown texture.
Source V. Hartikainen