The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
One more brick pattern. A bit more depth to this one.
Source Benjamin Ward
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
This yellow background consists of a pattern of glossy gold buttons arranged in polka dot style on a seamless texture. Here's a pale yellow background pattern. Feel free to use it for your needs!
Source V. Hartikainen
Here's a brown background pattern with subtle stripes. I hope you'll like the color. If not, feel free to change it using an image editor, if you know how of course. Personally, I'm using GIMP to create these backgrounds.
Source V. Hartikainen
The image depicts a seamless pattern made using a bird's face.
Source Yamachem
Prismatic Abstract Line Art Pattern Background
Source GDJ
Sort of reminds me of those old house wallpapers.
Source Tish
Inspired by a 1930s wallpaper pattern I saw on TV.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Tile-able Dark Brown Wood Background. Feel free to use it as a background image in your designs or somewhere on the web. By the way, the color seems to be close to Coffee Brown.
Source V. Hartikainen
Seamless pattern inspired by a drawing on Pixabay. To get the tile this is formed from, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A seamless pattern created from a square tile. To get the tile, select the pattern in Inkscape and use shift+alt+i.
Source Firkin
It was called Navy Blue, but I made it dark. You know, the way I like it.
Source Ethan Hamilton
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Prismatic Geometric Pattern Background No Black
Source GDJ
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Zero CC tileable moss or lichen covered stone texture, edited from pixabay. CC0
Source Sojan Janso
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
Prismatic Abstract Geometric Background 2
Source GDJ
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
A version without colours blended together to give a different look.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A free seamless background pattern for use on websites.
Source V. Hartikainen
Zero CC bark from fur tree tileable texture, photographed and made by me. CC0
Source Sojan Janso
People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
The starting point for this was drawn on the web site steamcoded.org/PolyskelionMaker.svg
Source Firkin
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin