Zero CC tileable ground (#2) cracked, crackled texture, made by me. CC0
Source Sojan Janso
From an image on opengameart.org shared by rubberduck.
Source Firkin
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
ZeroCC tileable moss texture, photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'Uit de geschiedenis der Heilige Stede te Amsterdam', Yohannes Sterck, 1898.
Source Firkin
An alternative colour scheme to the original seamless pattern.
Source Firkin
An abstract web texture of a polished blue stone (or does it look more like ice).
Source V. Hartikainen
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
A pattern derived from part of a fractal rendering in Paint.net.
Source Firkin
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
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
Prismatic Triangular Seamless Pattern III With Background
Source GDJ
A white version of the very popular linen pattern.
Source Ant Ekşiler
Number five from the same submitter, makes my job easy.
Source Dima Shiper
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
Prismatic Chevrons Pattern 5 With Background
Source GDJ
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A comeback for you: the popular Escheresque, now in black.
Source Patten
Lovely pattern with some good-looking non-random noise lines.
Source Zucx