To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A background tile for web with abstract repeating texture of dark "stone wall".
Source V. Hartikainen
Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
Dark Tile-able Grunge Texture. I think this texture can be classified as grunge. It's free and seamless, as always.
Source V. Hartikainen
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Remixed from a drawing in 'Analecta Eboracensia', Thomas Widdrington, 1897.
Source Firkin
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Greyscale version of a pattern that came out of playing with the 'slinky' plug-in for Paint.net
Source Firkin
A web texture of brown canvas. Will look great, when used in dark web designs.
Source V. Hartikainen
Inspired by a drawing in 'Kulturgeschichte', Freidrich Hellwald, 1896.
Source Firkin
From a drawing in 'Two Women in the Klondike', Mary Hitchcock, 1899.
Source Firkin
From a drawing in 'Danmarks Riges Historie af J. Steenstrup, Kr. Erslev, A. Heise, V. Mollerup, J. A. Fridericia, E. Holm, A. D. Jørgensen', 1897.
Source Firkin