A comeback for you: the popular Escheresque, now in black.
Source Patten
Seamless pattern the basic tile for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Farmer could be some sort of fabric pattern, with a hint of green.
Source Fabian Schultz
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
Prismatic Groovy Concentric Background 3 No Black
Source GDJ
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
Pattern formed from simple shapes. Black version.
Source Firkin
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Real snow that tiles, not easy. This is not perfect, but an attempt.
Source Atle Mo
From an image on opengameart.org shared by rubberduck.
Source Firkin
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Zero CC tileable cork floor, photographed and made by me. CC0
Source Sojan Janso
A bit strange this one, but nice at the same time.
Source Diogo Silva
He influenced us all. “Don’t be sad because it’s over. Smile because it happened.”
Source Atle Mo
First pattern tailor-made for Retina, with many more to come. All the old ones are upscaled, in case you want to re-download.
Source Atle Mo
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Might not be super subtle, but quite original in its form.
Source Alex Smith
In the spirit of WWDC 2011, here is a dark iOS inspired linen pattern.
Source Atle Mo
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
A seamless pattern drawn originally in Paint.net by distorting a slice of background pattern 116 and copying the resulting triangle numerous times.
Source Firkin
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks. https://cloaks.deviantart.com
Source Atle Mo
A seamless background colored in pale orange. It has a paper like texture with diagonal grid pattern.
Source V. Hartikainen
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
Someone was asking about how to achieve a fur pattern at #inkscape irc so tried to make a filter on it. Flood filled fractal noises rigged together. May someone find a good use for these.
Source Lazur URH
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin