Seamless pattern the basic tile for which can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
Embossed lines and squares with subtle highlights.
Source Alex Parker
Feel free to download and use it, or see the rest of the dark background patterns that I have made. Anyway, I hope you will find something that you like.
Source V. Hartikainen
From a drawing in 'A Life Interest', Mrs Alexander, 1888.
Source Firkin
Sharp but soft triangles in light shades of gray.
Source Pixeden
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
Bright gray tones with a hint of some metal surface.
Source Hendrik Lammers
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
Light and tiny, just the way you like it.
Source Rohit Arun Rao