Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Same classic 45-degree pattern, dark version.
Source Luke McDonald
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Tiny, tiny 3D cubes. Reminds me of the good old pattern from k10k.
Source Etienne Rallion
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett