Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
A repeating gloomy background image. This one consists of a pattern of black chains layered on top of a dark textured background.
Source V. Hartikainen
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
A dark metal plate with an embossed grid pattern and a bit of rust. Here's a dark metal plate texture for use as a tiled background on web pages.
Source V. Hartikainen
From a drawing in 'Kingsdene', Maria Fetherstonehaugh, 1878.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
Feel free to use this seamless background texture as a background on a web site. It's colored in a light pink color and is seamlessly tile-able.
Source V. Hartikainen
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
Here I have tried to create something that would look like maple wood. Not sure how well it's turned out, but at least it looks like wood.
Source V. Hartikainen
A white version of the very popular linen pattern.
Source Ant Ekşiler
By popular request, an outline version of the pentagon pattern.
Source Atle Mo