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
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
A blue background wallpaper for websites. It has a seamless texture with vertical stripes. It looks quite nice not only when using as a tiled background on websites, but also on computer desktops.
Source V. Hartikainen
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Classic vertical lines, in all its subtlety.
Source Cody L
From a drawing in 'Hubert Montreuil, or the Huguenot and the Dragoon', Francisca Ouvry, 1873.
Source Firkin
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Traced from a drawing in 'Household Stories from the Collection of the Brothers Grimm', Wilhelm Carl Grimm , 1882.
Source Firkin
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
I have no idea what J Boo means by this name, but hey – it’s hot.
Source j Boo
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
With a name like this, it has to be hot. Diagonal lines in light shades.
Source Isaac
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
Tiny little flowers growing on your screen. Nice, huh?
Source Themes Tube
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
A chequerboard pattern with a fruit theme. The fruits are from a posting by inkscapeforum.it.
Source Firkin
You know I love paper patterns. Here is one from Stephen. Say thank you!
Source Stephen Gilbert
Derived from a corner decoration itself found as a jpg on Pixabay.
Source Firkin
You know I’m a sucker for these. Well-crafted paper pattern.
Source Mihaela Hinayon
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
Prismatic Abstract Geometric Background 2
Source GDJ