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
Derived from an image that was uploaded to Pixabay by pugmom40
Source Firkin
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
I’m guessing this is related to the Sony Vaio? It’s a nice pattern no matter where it’s from.
Source Zigzain
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
One more sharp little tile for you. Subtle circles this time.
Source Blunia
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Abstract Tiled Background Extended 6
Source GDJ
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Prismatic Floral Pattern 3 Variation 3 No Background
Source GDJ
Submitted by DomainsInfo – wtf, right? But hey, a free pattern.
Source DomainsInfo
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
This is the remix of "polka dot seamless pattern".The image depicts polka dot seamless pattern.
Source Yamachem
This ladies and gentlemen, is texturetastic! Love it.
Source Adam Pickering
Subtle scratches on a light gray background.
Source Andrey Ovcharov
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Not the Rebel alliance, but a dark textured pattern.
Source Hendrik Lammers