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
The image is a remix of "edo pattern-samekomon".I changed the color of dots from black to white and added BG in light-yellow.
Source Yamachem
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Dare I call this a «flat pattern»? Probably not.
Source Dax Kieran
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
The Grid. A digital frontier. I tried to picture clusters of information as they traveled through the computer.
Source Haris Šumić
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
Pattern formed from simple shapes. Black version.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Abstract Line Art Pattern Background
Source GDJ
Prismatic Abstract Geometric Background 4
Source GDJ
White little knobs, coming in at 10x10px. Sweet!
Source Amos
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A free seamless background pattern for use on websites.
Source V. Hartikainen
Prismatic Hypnotic Pattern No Background
Source GDJ
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
A good starting point for a cardboard pattern. This would work well in a variety of colors.
Source Atle Mo