Might not be super subtle, but quite original in its form.
Source Alex Smith
This one is super crisp at 2X. Lined paper with some dust and scratches.
Source HQvectors
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
This white background pattern has a seamless grunge style texture. Here's a white grunge style background pattern. Use it as a tiled background image on web sites or for other purposes.
Source V. Hartikainen
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
Little x’es, noise and all the stuff you like. Dark like a Monday, with a hint of blue.
Source Tom McArdle
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Dark pattern with some nice diagonal stitched lines crossing over.
Source Ashton
Made by distorting a simple pattern using the 'sin waves' plugin for Paint.net and vectorising in Vector Magic
Source Firkin
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
A lot of people like the icon patterns, so here’s one for your restaurant blog.
Source Andrijana Jarnjak
Plywood Web Background background image for use in web design.
Source V. Hartikainen
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The image depicts a seamless pattern which was made using stripe-like things including borders.I used OCAL cliparts called "Blue Greek Key With Lines Border" uploaded by "GR8DAN" and "daisy border" uploaded by "johnny_automatic".Thanks.
Source Yamachem
A free background image with a seamless texture of cardboard. This texture of cardboard looks quite realistic, especially when is actually tiled.
Source V. Hartikainen
Black version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
From a drawing in 'Uit de geschiedenis der Heilige Stede te Amsterdam', Yohannes Sterck, 1898.
Source Firkin
I have no idea how to describe this one, but it’s light and delicate.
Source JBasoo
A seamless pattern based on a rectangular tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
Kaleidoscope Prismatic Abstract No Background
Source GDJ