This is so subtle you need to bring your magnifier!
Source Carlos Valdez
As the original image 's page size is too large for its image size, I remixed it.
Source Yamachem
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Based on an image that was uploaded to Pixabay by devanath
Source Firkin
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A classic dark tile for a bit of vintage darkness.
Source Listvetra
Dark and hard, just the way we like it. Embossed triangles makes a nice pattern.
Source Ivan Ginev
A seamless dark leather-like background texture with diagonal lines that look like stitches.
Source V. Hartikainen
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
Prismatic Polyskelion Pattern No Background
Source GDJ
Embossed lines and squares with subtle highlights.
Source Alex Parker
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A pale yellow background pattern with vertical stripes. The stripes are partially faded. I think this background image turned out pretty well, especially those faded stripes.
Source V. Hartikainen
This was formed by distorting an image of a background on Pixabay.
Source Firkin