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
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
Tweed is back in style – you heard it here first. Also, the @2X version here is great!
Source Simon Leo
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
A seamless pattern formed from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Light gray version of the Binding pattern that looks a bit like fabric.
Source Newbury
I’m not going to lie – if you submit something with the words Norwegian and Rose in it, it’s likely I’ll publish it.
Source Fredrik Scheide
This one is quite simple in design, it consists of vertical stripes layered on top of a seamless texture.
Source V. Hartikainen
I love cream! 50x50px and lovely in all the good ways.
Source Thomas Myrman
Seamless pattern made from a tile that can be obtained in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
The image depicts the Japanese Edo pattern called "seigaiha" or "青海波" meaning "blue -sea- wave".I hope it's suitable for the summer season.
Source Yamachem
Washi (和紙?) is a type of paper made in Japan. Here’s the pattern for you!
Source Carolynne
A light background pattern with diagonal stripes. Here's a simple light striped background for you.
Source V. Hartikainen
Like the name suggests, this background image consists of a pattern of dark bricks. It may be an option for you, if you are looking for something that looks like a brick wall for use as a background on web pages. It's not a masterpiece, but looks pretty nice when is tiled.
Source V. Hartikainen
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
A textured blue background pattern with vertical stripes.
Source V. Hartikainen
A beautiful dark padded pattern, like an old classic sofa.
Source Chris Baldie
8 by 8 pixels, and just what the title says.
Source pixilated
There are quite a few grid patterns, but this one is a super tiny grid with some dust for good measure.
Source Dominik Kiss
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin
Dark blue concrete wall with some small dust spots.
Source Atle Mo
The name Paisley reminds me of an old British servant. That’s just me.
Source Swetha
Abstract Stars Geometric Pattern Prismatic No Background
Source GDJ
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
From an image on opengameart.org shared by rubberduck.
Source Firkin