A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
Prismatic Abstract Background Design
Source GDJ
Tile-able Dark Brown Wood Background. Feel free to use it as a background image in your designs or somewhere on the web. By the way, the color seems to be close to Coffee Brown.
Source V. Hartikainen
This one is something special. I’d call it a flat pattern, too. Very well done, sir!
Source GetDiscount
This one could be the shirt of a golf player. Angled lines in different thicknesses.
Source Olivier Pineda
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
It’s big, it’s gradient—and it’s square.
Source Brankic1979
A repeating background of beige (or is it more vanilla yellow) textured stripes. One more background with stripes.
Source V. Hartikainen
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i
Source Firkin
You know, tiny and sharp. I’m sure you’ll find a use for it.
Source Atle Mo
The base gradient edited so now more details are rendered.
Source Lazur URH
Super detailed 16×16 tile that forms a beautiful pattern of straws.
Source Pavel
Feel free to use this seamless background texture as a background on a web site. It's colored in a light pink color and is seamlessly tile-able.
Source V. Hartikainen
Same as Silver Scales, but in black. Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Uses spirals from Pixabay. To get the basic tile select the rectangle in Inkscape and use shift+alt+i
Source Firkin