A comeback for you: the popular Escheresque, now in black.
Source Patten
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
Floral patterns might not be the hottest thing right now, but you never know when you need it!
Source Lauren
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Derived from an image that was uploaded to Pixabay by mdmelo.
Source Firkin
Same as Silver Scales, but in black. Turn your site into a dragon with this great scale pattern.
Source Alex Parker
A free green background pattern with a pattern of rhombuses on a seamless texture. Feel free to use it as a tiled background image on your web site.
Source V. Hartikainen
An interesting dark spotted pattern at an angle.
Source Hendrik Lammers
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
I scanned a paper coffee cup. You know, in case you need it.
Source Atle Mo
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks. https://cloaks.deviantart.com
Source Atle Mo
Inspired by the B&O Play, I had to make this pattern.
Source Atle Mo
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
It almost looks a bit blurry, but then again, so are fishes.
Source Petr Šulc
Floral patterns will never go out of style, so enjoy this one.
Source Lasma
As simple and subtle as it gets. But sometimes that’s just what you want.
Source Designova
Number 1 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Dark, crisp and subtle. Tiny black lines on top of some noise.
Source Wilmotte Bastien