In the spirit of WWDC 2011, here is a dark iOS inspired linen pattern.
Source Atle Mo
Prismatic Curved Diamond Pattern 6 No Background
Source GDJ
A chequerboard pattern with a fruit theme. The fruits are from a posting by inkscapeforum.it.
Source Firkin
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
A comeback for you: the popular Escheresque, now in black.
Source Patten
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
A free pink background pattern.
Source V. Hartikainen
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
The classic 45-degree diagonal line pattern, done right.
Source Jorick van Hees
Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
A repeating background with dark brown stone-like texture and abstract pattern that looks like tree trunks.
Source V. Hartikainen
Medium gray fabric pattern with 45-degree lines going across.
Source Atle Mo
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
Colour version that is close to the original drawing uploaded to Pixabay by pencilparker.
Source Firkin
Submitted in a cream color, but you know how I like it.
Source Devin Holmes
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso