Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
Luxurious looking pattern (for a T-shirt maybe?) with a hint of green.
Source Simon Meek
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
Might not be super subtle, but quite original in its form.
Source Alex Smith
Number 4 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
The tile this is based on can be had by selecting the rectangle in Inkscape 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
Zero CC tileable wood texture, made by me procedurally in Neo Texture Edit.
Source Sojan Janso
A heavy hitter at 400x400px, but lovely still.
Source Breezi
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Inspired by a JPG that was uploaded to Pixabay by kokon_art
Source Firkin
A seamless pattern of "sewn stripes" colored in light gray.
Source V. Hartikainen
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
From a drawing in 'A Life Interest', Mrs Alexander, 1888.
Source Firkin