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
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen
Everyone loves a diamond, right? Make your site sparkle.
Source AJ Troxell
A background tile of dark textile. Made this a long time ago and just now decided to publish it.
Source V. Hartikainen
Prismatic Curved Diamond Pattern No Background
Source GDJ
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
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
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
A dark striped seamless pattern suitable for use as a background on websites.
Source V. Hartikainen
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
No idea what Nistri means, but it’s a crisp little pattern nonetheless.
Source Markus Reiter
You know you can’t get enough of these linen-fabric-y patterns.
Source James Basoo
Psychedelic Geometric Background No Black
Source GDJ
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin