Formed by distorting a JPG from PublicDomainPictures
Source Firkin
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Retro Circles Background 4 No Black
Source GDJ
This background image has seamless texture that resembles a surface of gray stone.
Source V. Hartikainen
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
The name Paisley reminds me of an old British servant. That’s just me.
Source Swetha
Zero CC tileable Crackled Cement (streaks) texture, photographed and made by me. CC0
Source Sojan Janso
A pattern derived from part of a fractal rendering in Paint.net.
Source Firkin
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
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
An alternative colour scheme to the original seamless pattern.
Source Firkin
Spice up your next school project with this icon background.
Source Swetha
ZeroCC tileabel stone granite texture, edited from pixabay. CC0
Source Sojan Janso
Remixed from an image on Pixabay uploaded by Prawny
Source Firkin
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
This background pattern contains a seamless texture of bark. It's not very realistic, but I think it looks quite nice.
Source V. Hartikainen
Prismatic Groovy Concentric Background 3
Source GDJ
More in the paper realm, this time with fibers.
Source Jorge Fuentes