A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
This is lovely, just the right amount of subtle noise, lines and textures.
Source Richard Tabor
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A beautiful dark wood pattern, superbly tiled.
Source Omar Alvarado
A bit strange this one, but nice at the same time.
Source Diogo Silva
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
A seamless green background texture. The image is distributed under a Creative Commons License (like all of the images here).
Source V. Hartikainen
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
Not the Rebel alliance, but a dark textured pattern.
Source Hendrik Lammers
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin