I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
Formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Little x’es, noise and all the stuff you like. Dark like a Monday, with a hint of blue.
Source Tom McArdle
First pattern tailor-made for Retina, with many more to come. All the old ones are upscaled, in case you want to re-download.
Source Atle Mo
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Seamless Dark Grunge Texture. Here's a new grunge texture for use as a background.
Source V. Hartikainen
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Prismatic Curved Diamond Pattern No Background
Source GDJ
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
This one needs to be used in small areas; you can see it repeat.
Source Luca
Submitted by DomainsInfo – wtf, right? But hey, a free pattern.
Source DomainsInfo
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
Did anyone say The Hoff? This pattern is in no way related to Baywatch.
Source Josh Green