All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
From a drawing in 'Real Sailor-Songs', John Ashton, 1891.
Source Firkin
Thin lines, noise and texture creates this crisp dark denim pattern.
Source Marco Slooten
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
Abstract Tiled Background Extended 8
Source GDJ
A bit of scratched up grayness. Always good.
Source Dmitry
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
This was formed by distorting an image of a background on Pixabay.
Source Firkin
From a drawing in 'Bond Slaves. The story of a struggle.', Isabella Varley, 1893.
Source Firkin
Someone was asking about how to achieve a fur pattern at #inkscape irc so tried to make a filter on it. Flood filled fractal noises rigged together. May someone find a good use for these.
Source Lazur URH
Might not be super subtle, but quite original in its form.
Source Alex Smith
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
A dark metallic background with a pattern of stamped dots. Here's a dark "metallic" background pattern for you.
Source V. Hartikainen