A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
Looks like an old wall. I guess that’s it then?
Source Viahorizon
Number five from the same submitter, makes my job easy.
Source Dima Shiper
Abstract Tiled Background Extended 6
Source GDJ
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A seamless pattern with a unit cell drawn as a bitmap in Paint.net and vectorized in Vector Magic.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
This one is amazing, truly original. Go use it!
Source Viahorizon
This texture looks like old leather. It should look great as a background on web pages.
Source V. Hartikainen
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin
A comeback for you: the popular Escheresque, now in black.
Source Patten
Mostly just mucked about with the colours and made one of the paths in the lead frame opaque. The glass remains transparent.
Source Firkin
This is the remix of an OCAL clipart called "Rain on Window" uploaded by "pagarmidna".Thanks.This is a seamless pattern of raindrops.
Source Yamachem
Some dark 45 degree angles creating a nice pattern. Huge.
Source Dark Sharp Edges
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Remixed from an image that was uploaded to Pixabay by KirstenStar
Source Firkin
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
Prismatic Chevrons Pattern 5 With Background
Source GDJ