Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
Prismatic Abstract Geometric Background 5
Source GDJ
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
Psychedelic Geometric Background No Black
Source GDJ
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Remixed from a raster on Pixabay, that was uploaded by ArtsyBee.
Source Firkin
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
A series of 5 patterns. That’s what the P stands for, if you didn’t guess it.
Source Dima Shiper
Colour version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868.
Source Firkin
Kaleidoscope Prismatic Abstract No Background
Source GDJ
Mostly just mucked about with the colours and made one of the paths in the lead frame opaque. The glass remains transparent.
Source Firkin
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
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
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Free tiled background with colorful stripes and white splatter.
Source V. Hartikainen
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Wasn't satisfied with the original's colouring. Too much component transfer and colormatrixes yet the results are lacking a bit. So this time it is a simple black to transparent fade, making it possible remixing easily once there will be other blending modes supported as well. Probably in inkscape 0.92.
Source Lazur URH