Might not be super subtle, but quite original in its form.
Source Alex Smith
Derived from a JPG that was uploaded to Pixabay by ractapopulous
Source Firkin
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Zero CC tileable wood texture, made by me procedurally in Neo Texture Edit.
Source Sojan Janso
Derived from a drawing in 'Historiske Afhandlinger', Adolf Jorgensen, 1898.
Source Firkin
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
Imagine you zoomed in 1000X on some fabric. But then it turned out to be a skeleton!
Source Angelica
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
This seamless pattern consists of a blue grid on a yellow background.
Source V. Hartikainen
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
A seamless pattern with a unit cell drawn as a bitmap in Paint.net and vectorized in Vector Magic.
Source Firkin
Tiny little flowers growing on your screen. Nice, huh?
Source Themes Tube
Farmer could be some sort of fabric pattern, with a hint of green.
Source Fabian Schultz
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
CC0 and seamless wellington boot pattern.
Source SliverKnight
Background Wall, Art Abstract, Watercolor Vintage style CC0 texture.
Source Ractapopulous
A dark gray, sandy pattern with small light dots, and some angled strokes.
Source Atle Mo
Just like your old suit, all striped and smooth.
Source Alex Berkowitz