Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
The tile can be had by using shift+alt+i on the selected rectangle in Inkscape
Source Firkin
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
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
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
This could be a hippy vintage wallpaper.
Source Tileable Patterns
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
A free background image with a seamless texture of cardboard. This texture of cardboard looks quite realistic, especially when is actually tiled.
Source V. Hartikainen
ZeroCC tileable stone texture, edited from pixabay, CC0
Source Sojan Janso
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A black tile-able background with paper-like texture.
Source V. Hartikainen
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
A criss-cross pattern similar to one I saw mown into a sports field.
Source Firkin
A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.
Source Lazur URH
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
A seamlessly tileable pink background texture.
Source V. Hartikainen
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim