Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim
Prismatic Abstract Line Art Pattern Background
Source GDJ
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
Prismatic Basic Pattern 2 No Background
Source GDJ
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Same classic 45-degree pattern, dark version.
Source Luke McDonald
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin