Prismatic Abstract Geometric Background 4 No Black
Source GDJ
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 mdmelo.
Source Firkin
A bit simplified version. Although it could be edited out to be simpler. Anyway, this time the tiling is converted to a pattern fill -which is using clipping for the tile's edges.
Source Lazur URH
Retro Circles Background 7 No Black
Source GDJ
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
A seamless pattern formed from a tile made from ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Luxury pattern, looking like it came right out of Paris.
Source Daniel Beaton
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A seamless background of warped stripes on paper.
Source V. Hartikainen
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Luxurious looking pattern (for a T-shirt maybe?) with a hint of green.
Source Simon Meek
Non-seamless pattern drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
From a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
Prismatic Chevrons Pattern 5 With Background
Source GDJ
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
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