A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Prismatic Groovy Concentric Background 4
Source GDJ
Prismatic Abstract Line Art Pattern Background
Source GDJ
8 by 8 pixels, and just what the title says.
Source pixilated
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
Prismatic Abstract Geometric Background 5
Source GDJ
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
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
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
A free black metallic background pattern. Here's a new pattern I made that looks metallic.
Source V. Hartikainen
A seamless texture of black leather. I think it will look best when used in headers, footers or sidebars.
Source V. Hartikainen
One more sharp little tile for you. Subtle circles this time.
Source Blunia
Submitted as a black pattern, I made it light and a few steps more subtle.
Source Andy
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
Remixed from a design on Pixabay. To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
The tile this fill pattern is based on can be had by using shift+alt+i on the rectangle.
Source Firkin
Lovely pattern with some good-looking non-random noise lines.
Source Zucx