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
8 by 8 pixels, and just what the title says.
Source pixilated
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
Prismatic Geometric Pattern Variation 2 With Background
Source GDJ
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
This one is something special. I’d call it a flat pattern, too. Very well done, sir!
Source GetDiscount
From an image on opengameart.org shared by rubberduck.
Source Firkin
Floral patterns will never go out of style, so enjoy this one.
Source Lasma
I have no idea how to describe this one, but it’s light and delicate.
Source JBasoo
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A beautiful dark padded pattern, like an old classic sofa.
Source Chris Baldie
The act or state of corrugating or of being corrugated, a wrinkle; fold; furrow; ridge.
Source Anna Litvinuk
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
A dark background pattern/texture of a dimpled metal plate.
Source V. Hartikainen
The image depicts a Japanese Edo pattern called "kanoko or 鹿の子" meaning "fawn" which has a fur with small white spots.
Source Yamachem
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A free black metallic background pattern. Here's a new pattern I made that looks metallic.
Source V. Hartikainen
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
If you’re sick of the fancy 3D, grunge and noisy patterns, take a look at this flat 2D brick wall.
Source Listvetra
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić