Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
It looks like a polished stone surface to me. Download it for free, as always.
Source V. Hartikainen
White circles connecting on a light gray background.
Source Mark Collins
Just a nice looking textured pattern with faded blue stripes. Well, that's it for today... one background a day, as usual.
Source V. Hartikainen
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Heavily remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Submitted by DomainsInfo – wtf, right? But hey, a free pattern.
Source DomainsInfo
A comeback for you: the popular Escheresque, now in black.
Source Patten
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Zero CC tileable wood texture, made by me procedurally in Neo Texture Edit.
Source Sojan Janso
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
From a drawing in 'Less Black than we're painted', James Payn, 1884.
Source Firkin
A repeating background of beige paper with vintage look. Repeats to infinity, as usual.
Source V. Hartikainen
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin