There are many carbon patterns, but this one is tiny.
Source Designova
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Zero CC tileable hard cover red book, scanned and made by me. CC0
Source Sojan Janso
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
I asked Gjermund if he could make a pattern for us – result!
Source Gjermund Gustavsen
The edges of all the red objects line up either vertically or horizontally, but it doesn't appear so. Made from a square tile that can be got by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A free tileable background colored in off-white (antique white) color.
Source V. Hartikainen
This beige background pattern resembles a concrete wall with engravings or something similar to it.
Source V. Hartikainen
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo
Luxurious looking pattern (for a T-shirt maybe?) with a hint of green.
Source Simon Meek
Remixed from a PNG that was uploaded to Pixabay by VictorianLady
Source Firkin
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A free seamless background pattern for use on websites.
Source V. Hartikainen
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin