Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
This background pattern looks like bamboo to me. Feel free to download it for your website (for your blog perhaps?).
Source V. Hartikainen
A very dark spotted twinkle pattern for your twinkle needs.
Source Badhon Ebrahim
A subtle shadowed checkered pattern. Increase the lightness for even more subtle sexiness.
Source Josh Green
Remixed from a JPG that was uploaded to Pixabay by theasad121
Source Firkin
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
This one resembles a black concrete wall when is tiled. It should look great, at least with dark website themes.
Source V. Hartikainen
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
This is a remix of "blue wave-seigaiha".I hope this subtle color version of Seigaiha would be suitable for background .
Source Yamachem
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim
That’s what it is, a dark dot. Or sort of carbon looking.
Source Tsvetelin Nikolov
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
Sort of reminds me of those old house wallpapers.
Source Tish
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
This background has abstract texture with some similarities to wood.
Source V. Hartikainen
The basic shapes never get old. Simple triangle pattern.
Source Atle Mo
The image depicts a seamless pattern which was made using stripe-like things including borders.I used OCAL cliparts called "Blue Greek Key With Lines Border" uploaded by "GR8DAN" and "daisy border" uploaded by "johnny_automatic".Thanks.
Source Yamachem
Remixed from an image on Pixabay, the original having been uploaded by darkmoon1968.
Source Firkin
Sweet and subtle white plaster with hints of noise and grunge.
Source Phil Maurer
A very dark asfalt pattern based off of a photo taken with my iPhone.
Source Atle Mo
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
Inspired by a pattern found in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin