Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A bit like smudged paint or some sort of steel, here is scribble light.
Source Tegan Male
Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.
Source Atle Mo
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
One more from Badhon, sharp horizontal lines making an embossed paper feeling.
Source Badhon Ebrahim
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Number 5 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Super simple but very nice indeed. Gray with vertical stripes.
Source Merrin Macleod
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
A free black metallic background pattern. Here's a new pattern I made that looks metallic.
Source V. Hartikainen
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
The tile can be had by using shift+alt+i on the selected rectangle in Inkscape
Source Firkin
A simple but elegant classic. Every collection needs one of these.
Source Christopher Burton
Zero CC tileable ground (#2) cracked, crackled texture, made by me. CC0
Source Sojan Janso
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
From a drawing in 'La Principauté de Liège et les Pays-Bas au XVIe siècle', Société des Bibliophiles Liégeois ,1887.
Source Firkin
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
A seamless pattern of leopard skin. It should look nice as a background element on web pages.
Source V. Hartikainen
Alternative colour scheme. Not a pattern for fabrics, but one produced from a jpg of a stack of fabric items that was posted on Pixabay. The tile that this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin