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
A seamless pattern of leopard skin. It should look nice as a background element on web pages.
Source V. Hartikainen
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
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
Imagine you zoomed in 1000X on some fabric. But then it turned out to be a skeleton!
Source Angelica
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless pattern of "sewn stripes" colored in light gray.
Source V. Hartikainen
High detail stone wall with minor cracks and specks.
Source Projecteightyfive
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-I.
Source Firkin
Zero CC tileable wood texture, made by me procedurally in Neo Texture Edit.
Source Sojan Janso
One more brick pattern. A bit more depth to this one.
Source Benjamin Ward
Here's a seamless brown cork board background texture. Feel free to download or reshare if you like.
Source V. Hartikainen
Psychedelic Geometric Background No Black
Source GDJ
A beautiful dark padded pattern, like an old classic sofa.
Source Chris Baldie
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Sometimes you just need the simplest thing.
Source Fabricio
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A seamless pattern formed from a square tile. The tile can be retrieved by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Black paper texture, based on two different images.
Source Atle Mo
Based from Design Kindle