To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
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
From a drawing in 'A Guide to the Guildhall of the City of London', John Baddeley, 1898.
Source Firkin
Looks as if it's spray painted on the wall. You can be sure that this pattern will seamlessly fill your backgrounds on web pages.
Source V. Hartikainen
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Tile available in Inkscape using shift-alt-i on the selected rectangle
Source Firkin
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
As simple and subtle as it gets. But sometimes that’s just what you want.
Source Designova
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
A seamless pattern formed from miutopia mug remixes on a tablecloth.
Source Firkin
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Prismatic Polyskelion Pattern No Background
Source GDJ
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
Heavy depth and shadows here, but might work well on some mobile apps.
Source Damian Rivas
This was formed by distorting an image of a background on Pixabay.
Source Firkin
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel