Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
Seamless pattern formed from a tile that 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
From a drawing in 'A Guide to the Guildhall of the City of London', John Baddeley, 1898.
Source Firkin
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
The texture of this background image has some similarities with leather, and it's colored in a dark brown color. So, if you are looking for a dark brown background image for your website, this may be an option for you.
Source V. Hartikainen
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
Prismatic Abstract Geometric Background 4
Source GDJ
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
8 by 8 pixels, and just what the title says.
Source pixilated
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Derived from an image that was uploaded to Pixabay by TheDigitalArtist
Source Firkin
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby