Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
Prismatic Curved Diamond Pattern 7 No Background
Source GDJ
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
If you don’t like cream and pixels, you’re in the wrong place.
Source Mizanur Rahman
Looks like an old rug or a computer chip.
Source Patutin Sergey
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Prismatic Abstract Background Design No Black
Source GDJ
Zero CC tileable Crackled Cement (streaks) texture, photographed and made by me. CC0
Source Sojan Janso
Zero CC tileable hard cover cells, skin like, book texture. 4K, Scanned and made by me CC0
Source Sojan Janso
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
A seamless pattern formed from a sports car on clker.com. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A pattern drawn in Paint.net and vectorized in Inkscape.
Source Firkin
Remixed from a raster on Pixabay, that was uploaded by ArtsyBee.
Source Firkin
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