A heavy hitter at 400x400px, but lovely still.
Source Breezi
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
From a drawing in 'A Life Interest', Mrs Alexander, 1888.
Source Firkin
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Seamless tile drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A nice one indeed, but I have a feeling we have it already? If you spot a copy, let me know on Twitter.
Source Graphiste
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Kaleidoscope Prismatic Abstract No Background
Source GDJ
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Fix and cc0 to get the tile this is based on.
Source SliverKnight
A seamless pattern formed from a modified version of rwwgub's tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Submitted as a black pattern, I made it light and a few steps more subtle.
Source Andy
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Background pattern originally a PNG drawn in Paint.net
Source Firkin