A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
Prismatic Snowflakes Pattern No Background
Source GDJ
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A version without colours blended together to give a different look.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
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
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
Here's a tile-able wood background image for use in web design.
Source V. Hartikainen
Retro Circles Background 4 No Black
Source GDJ
Colour version of the original pattern.
Source Firkin
A seamless stone-like background for blogs or any other type of websites.
Source V. Hartikainen
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
One more in the line of patterns inspired by Japanese/Asian styles. Smooth.
Source Kim Ruddock
A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin