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
Thin lines, noise and texture creates this crisp dark denim pattern.
Source Marco Slooten
This reminds me of Game Cube. A nice light 3D cube pattern.
Source Sander Ottens
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
Dark squares with some virus-looking dots in the grid.
Source Hugo Loning
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Inspired by this, I came up with this pattern. Madness!
Source Atle Mo
Here's an yet another seamless note paper texture for use as a background on websites.
Source V. Hartikainen
The image depicts a seamless pattern of pine tree leaves.
Source Yamachem
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
An abstract pale yellow paper-like background with stains colored in yellow and green.
Source V. Hartikainen
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'A Rolling Stone. A tale of wrongs and revenge', John Hartley, 1878.
Source Firkin
A large (588x375px) sand-colored pattern for your ever-growing collection. Shrink at will.
Source Alex Tapein
A pale orange background pattern with glossy groove stripes.
Source V. Hartikainen
Actually, there's no clouds in it, but I think it looks quite nice.
Source V. Hartikainen
Three shades of gray makes this pattern look like a small carbon fiber surface. Great readability even for small fonts.
Source Atle Mo