Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
You know you can’t get enough of these linen-fabric-y patterns.
Source James Basoo
Here's a quite bright pink background pattern for use on websites. It doesn't look like a real fur, but it definitely resembles one.
Source V. Hartikainen
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
I love cream! 50x50px and lovely in all the good ways.
Source Thomas Myrman
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
Can never have too many knitting patterns, especially as nice as this.
Source Victoria Spahn
Seamless Light Background Texture.
Source V. Hartikainen
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Very dark pattern with some noise and 45-degree lines.
Source Stefan Aleksić
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
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
Remixed from a drawing in 'Canadian forest industries July-December', 1915
Source Firkin
This background has abstract texture with some similarities to wood.
Source V. Hartikainen
You know, tiny and sharp. I’m sure you’ll find a use for it.
Source Atle Mo
As simple and subtle as it gets. But sometimes that’s just what you want.
Source Designova
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS