Here's a subtle marble-like background for use on websites.
Source V. Hartikainen
Prismatic Geometric Pattern Background 2
Source GDJ
Light gray grunge wall with a nice texture overlay.
Source Adam Anlauf
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
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 texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
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
The image depicts a seamless pattern of the design which includes a stylized lotus and a stylized crane.I referred to the original image in a book which is into public domain.
Source Yamachem
Tiny little fibers making a soft and sweet look.
Source Badhon Ebrahim
No idea what Nistri means, but it’s a crisp little pattern nonetheless.
Source Markus Reiter
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Black & white version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Nice and simple crossed lines in dark gray tones.
Source Stefan Aleksić
A seamless pattern with wide vertical stripes colored in pale yellow.
Source V. Hartikainen
Run a restaurant blog? Here you go. Done.
Source Andrijana Jarnjak
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Carbon fiber is never out of fashion, so here is one more style for you.
Source Alfred Lee
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin