This one needs to be used in small areas; you can see it repeat.
Source Luca
It’s okay to be square! A nice light gray pattern with random squares.
Source Waseem Dahman
An abstract texture of black metal pipes (seamless).
Source V. Hartikainen
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Retro Circles Background 7 No Black
Source GDJ
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
Did anyone say The Hoff? This pattern is in no way related to Baywatch.
Source Josh Green
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Little x’es, noise and all the stuff you like. Dark like a Monday, with a hint of blue.
Source Tom McArdle
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A seamless pattern formed from a square tile based on a jpg on Pixabay. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
Traced from a drawing in 'Household Stories from the Collection of the Brothers Grimm', Wilhelm Carl Grimm , 1882.
Source Firkin
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
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
The original enhanced with one of Inkscapes's filters.
Source Firkin
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Zero CC tileable ground cracked, crackled, texture, made by me.
Source Sojan Janso
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin