People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
Pass parameters to the URL or edit the source code variables to configure the graph paper for the division desired.
Source JayNick
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
New paper pattern with a slightly organic feel to it, using some thin threads.
Source Atle Mo
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
Zero CC bark from fur tree tileable texture, photographed and made by me. CC0
Source Sojan Janso
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein