Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
A lovely light gray pattern with stripes and a dash of noise.
Source V. Hartikainen
Background pattern originally a PNG drawn in Paint.net
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
I guess this one is inspired by an office. A dark office.
Source Andrés Rigo.
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
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
The image is a seamless pattern which is derived from a vine .Consequently, the vine got like dots via vectorization.The original vine is here:jp.pinterest.com/pin/500744052301410188/
Source Yamachem
Fix and cc0 to get the tile this is based on.
Source SliverKnight
This is sort of fresh, but still feels a bit old school.
Source Martuchox
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
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
Abstract Tiled Background Extended 12
Source GDJ
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This texture looks like old leather. It should look great as a background on web pages.
Source V. Hartikainen
Remix from a drawing in 'Ostatnie chwile powstania styczniowego', Zygmunt Sulima, 1887.
Source Firkin
Here I have tried to create something that would look like maple wood. Not sure how well it's turned out, but at least it looks like wood.
Source V. Hartikainen
Black brick wall pattern. Brick your site up!
Source Alex Parker
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars