I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
You know I’m a sucker for these. Well-crafted paper pattern.
Source Mihaela Hinayon
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
From a drawing in 'Hubert Montreuil, or the Huguenot and the Dragoon', Francisca Ouvry, 1873.
Source Firkin
A background pattern with blue on white vertical stripes.
Source V. Hartikainen
Prismatic Abstract Background Design No Black
Source GDJ
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
A seamless pattern recreated from an image on Pixabay. It is reminiscent of parquet flooring and is formed from a square tile, which can be recovered in Inkscape by selecting the ungrouped rectangle and using shift-alt-I together.
Source Firkin
A free seamless background with pink spots.
Source V. Hartikainen
Based on an image that was uploaded to Pixabay by devanath
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Black version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
I love cream! 50x50px and lovely in all the good ways.
Source Thomas Myrman
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
Prismatic Groovy Concentric Background 5
Source GDJ