Alternative colour scheme. 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
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
Prismatic Groovy Concentric Background 2 No Black
Source GDJ
White fabric looking texture with some nice random wave features.
Source Hendrik Lammers
One more sharp little tile for you. Subtle circles this time.
Source Blunia
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
A very dark spotted twinkle pattern for your twinkle needs.
Source Badhon Ebrahim
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
This was formed by distorting an image of a background on Pixabay.
Source Firkin
A seamless pattern formed from cross 4. To get the original tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Dark Tile-able Grunge Texture. I think this texture can be classified as grunge. It's free and seamless, as always.
Source V. Hartikainen
A free pink background pattern.
Source V. Hartikainen
You may use it as is, or modify it as you like.
Source V. Hartikainen
A seamless pattern drawn originally in Paint.net by distorting a slice of background pattern 116 and copying the resulting triangle numerous times.
Source Firkin
Abstract Tiled Background Extended 11
Source GDJ
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers