A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
Background Wall, Art Abstract, white Well & CC0 texture.
Source Ractapopulous
Dark blue concrete wall with some small dust spots.
Source Atle Mo
Prismatic Curved Diamond Pattern No Background
Source GDJ
This metal background pattern resembles a metal plate with rivets. Solid rivets on a metal plate.
Source V. Hartikainen
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
An orange vertically striped background pattern. Feel free to download and use this orange background pattern, for example, on the web). It resembles a wallpaper with vertical stripes or something similar to it.
Source V. Hartikainen
Remixed from a PNG that was uploaded to Pixabay by k_jprather
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Prismatic Groovy Concentric Background 5
Source GDJ
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A pattern formed from a photograph of a 16th century ceramic tile.
Source Firkin