This is a hot one. Small, sharp and unique.
Source GraphicsWall
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
From a drawing in 'Az Osztrák-Magyar Monarchia irásban és képben', 1885.
Source Firkin
A seamless web texture of "green stone".
Source V. Hartikainen
Prismatic Rounded Squares Grid 4 No Background
Source GDJ
From a drawing in 'Royal Ramsgate', James Simson, 1897.
Source Firkin
Traced from a drawing in 'Household Stories from the Collection of the Brothers Grimm', Wilhelm Carl Grimm , 1882.
Source Firkin
Inspired by a pattern found in 'A General History of Hampshire, or the County of Southampton, including the Isle of Wight', Bernard Woodwood, 1861
Source Firkin
From a drawing in 'A Life Interest', Mrs Alexander, 1888.
Source Firkin
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
Imagine you zoomed in 1000X on some fabric. But then it turned out to be a skeleton!
Source Angelica
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
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
We have some linen patterns here, but none that are stressed. Until now.
Source Jordan Pittman
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
Remixed from a PNG that was uploaded to Pixabay by gingertea
Source Firkin
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
A tile-able background for websites with paper-like texture and a grid pattern layered on top of it.
Source V. Hartikainen