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
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
I’m guessing this is related to the Sony Vaio? It’s a nice pattern no matter where it’s from.
Source Zigzain
A seamless pattern formed from a sports car on clker.com. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
Zero CC tileable bark texture, photographed and made by me. CC0
Source Sojan Janso
Derived from an image that was uploaded to Pixabay by starchim01
Source Firkin
A seamless pattern formed from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The texture of this background image has some similarities with leather, and it's colored in a dark brown color. So, if you are looking for a dark brown background image for your website, this may be an option for you.
Source V. Hartikainen
Fake or not, it’s quite luxurious.
Source Factorio.us Collective
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
Formed by distorting a JPG from PublicDomainPictures
Source Firkin
Based on an image that was uploaded to Pixabay by devanath
Source Firkin
This seamless background image should look nice on websites. It has a dark blue gray texture with vertical stripes, it tiles seamlessly and, like all of the background images here, it's free. So, if you like it, take it!
Source V. Hartikainen
Could be paper, could be a Polaroid frame – up to you!
Source Chaos
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A repeating background with wood/straw like texture.
Source V. Hartikainen
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
Seamless pattern formed from a tile that can be extracted by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin