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
The image depicts a seamless pattern made using a bird's face.
Source Yamachem
This background pattern contains worn out colorful stripes as a texture.
Source V. Hartikainen
Zero CC tileable seed texture, edited by me to be seamless from a Pixabay image. CC0
Source Sojan Janso
Heavily remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
Simple combination of stripy squares with their negatively coloured counterparts
Source Firkin
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
This one needs to be used in small areas; you can see it repeat.
Source Luca
A seamless paper background colored in pale yellow.
Source V. Hartikainen
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav
The tile this fill pattern is based on can be had by using shift+alt+i on the rectangle.
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
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin