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
Prismatic Abstract Background Design No Black
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
First pattern tailor-made for Retina, with many more to come. All the old ones are upscaled, in case you want to re-download.
Source Atle Mo
Same classic 45-degree pattern, dark version.
Source Luke McDonald
Remixed from a drawing that was uploaded to Pixabay by DavidZydd
Source Firkin
Prismatic Abstract Geometric Background 5 No Black
Source GDJ
The starting point for this was drawn on the web site steamcoded.org/PolyskelionMaker.svg
Source Firkin
From a drawing in 'A Rolling Stone. A tale of wrongs and revenge', John Hartley, 1878.
Source Firkin
Super detailed 16×16 tile that forms a beautiful pattern of straws.
Source Pavel
Coming in at 666x666px, this is an evil big pattern, but nice and soft at the same time.
Source Atle Mo
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
From a drawing in 'Danmarks Riges Historie af J. Steenstrup, Kr. Erslev, A. Heise, V. Mollerup, J. A. Fridericia, E. Holm, A. D. Jørgensen', 1897.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Same as the black version, but now in shades of gray. Very subtle and fine grained.
Source Atle Mo