Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
The file was named striped lens, but hey – Translucent Fibres works too.
Source Angelica
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
A smooth mid-tone gray, or low contrast if you will, linen pattern.
Source Jordan Pittman
Zero CC tileable hard cover cells book texture, 4k, scanned and made by me. CC0
Source Sojan Janso
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
A seamless design of flowers remixed from a jpg on Pixabay by Prawny.
Source Firkin
Have you wondered about how it feels to be buried alive? Here is the pattern for it.
Source Hendrik Lammers
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
A free background image with a seamless texture of cardboard. This texture of cardboard looks quite realistic, especially when is actually tiled.
Source V. Hartikainen
These dots are already worn for you, so you don’t have to.
Source Matt McDaniel
A simple example on using clones. You can generate a nice base for a pattern fill quickly with it.
Source Lazur URH
This one is something special. I’d call it a flat pattern, too. Very well done, sir!
Source GetDiscount
A seamless pattern with wide vertical stripes colored in pale yellow.
Source V. Hartikainen
This is a remix of "geometrical pattern 01".
Source Yamachem
Background Wall, Art Abstract, Watercolor Vintage style CC0 texture.
Source Ractapopulous
As the original image 's page size is too large for its image size, I remixed it.
Source Yamachem
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
Here's a new paper-like background for free use on personal and commercial projects (this applies to all background patterns here).
Source V. Hartikainen