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
Redrawn based on a drawing in 'По Сѣверо-Западу Россіи' Konstantin Sluchevsky, 1897.
Source Firkin
Zero CC tileable brick texture, photographed and made by me. CC0
Source Sojan Janso
A browner version of the original weathered fence texture.
Source Firkin
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
A free seamless background with pink spots.
Source V. Hartikainen
Floral patterns will never go out of style, so enjoy this one.
Source Lasma
The image is a seamless pattern of a fishnet.
Source Yamachem
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
From a design in 'Storia del Palazzo Vecchio in Firenze', Aurelio Gotti, 1889.
Source Firkin
Farmer could be some sort of fabric pattern, with a hint of green.
Source Fabian Schultz
Could remind you a bit of those squares in Super Mario Bros, yeh?
Source Jeff Wall
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Hey, you never know when you’ll need a bird pattern, right?
Source Pete Fecteau
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
Colour version of the original pattern.
Source Firkin
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
A set of paper filters. The base texture is generated the same way, only the compositing mode is varied.
Source Lazur URH
Formed from decorative divider 184 in paint.net. Vectorised with Vector Magic.
Source Firkin
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
A mid-tone gray pattern with some cement looking texture.
Source Hendrik Lammers
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ