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
Retro Circles Background 8 No Black
Source GDJ
Textured Red Brown Plastic, Free Background Pattern. Although there's already enough plastic in our lives, let's bring it to the web too.)
Source V. Hartikainen
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
Super detailed 16×16 tile that forms a beautiful pattern of straws.
Source Pavel
A new take on the black linen pattern. Softer this time.
Source Atle Mo
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
I skipped number 3, because it wasn’t all that great. Sorry.
Source Dima Shiper
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
This reminds me of Game Cube. A nice light 3D cube pattern.
Source Sander Ottens
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
More Japanese-inspired patterns, Gold Scales this time.
Source Josh Green
Remixed from a drawing in 'Kulturgeschichte der Deutschen im Mittelalter' Franz von Loeher, 1891. The unit tile can be had by selecting the rectangle in Inkscape and using shift-alt-i
Source Firkin
A seamless background of warped stripes on paper.
Source V. Hartikainen
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
Tweed is back in style – you heard it here first. Also, the @2X version here is great!
Source Simon Leo
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
This one is quite simple in design, it consists of vertical stripes layered on top of a seamless texture.
Source V. Hartikainen
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim