The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
Little x’es, noise and all the stuff you like. Dark like a Monday, with a hint of blue.
Source Tom McArdle
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
Remixed from an image on Pixabay uploaded by Prawny
Source Firkin
Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
Might not be super subtle, but quite original in its form.
Source Alex Smith
The original enhanced with one of Inkscapes's filters.
Source Firkin
You were craving more leather, so I whipped this up by scanning a leather jacket.
Source Atle Mo
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
Background pattern originally a PNG drawn in Paint.net
Source Firkin
A background pattern with green vertical stripes. A new striped background pattern. This time a green one.
Source V. Hartikainen
The square tile this is based on 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
ZeroCC tileable mossy (lichen) stone texture, edited from pixabay. CC0
Source Sojan Janso
There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin