A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
Dark blue concrete wall with some small dust spots.
Source Atle Mo
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
8 by 8 pixels, and just what the title says.
Source pixilated
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
A free seamless background pattern for use on websites.
Source V. Hartikainen
Remixed from a PNG that was uploaded to Pixabay by gingertea
Source Firkin
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
From a drawing in 'Codogno e il suo territorio nella cronaca e nella storia'', Gio and Giarella Cairo, 1897.
Source Firkin
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
Alternative colour scheme for the original floral pattern.
Source Firkin
Prepared mostly as a raster in Paint.net and vectorised.
Source Firkin
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
This ladies and gentlemen, is texturetastic! Love it.
Source Adam Pickering
Formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
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