Might not be super subtle, but quite original in its form.
Source Alex Smith
Neat little photography icon pattern.
Source Hossam Elbialy
Prismatic Geometric Pattern Background
Source GDJ
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
I love cream! 50x50px and lovely in all the good ways.
Source Thomas Myrman
This one resembles a black concrete wall when is tiled. It should look great, at least with dark website themes.
Source V. Hartikainen
Looks like an old wall. I guess that’s it then?
Source Viahorizon
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
The classic subtle pattern. Sort of wall/brick looking. Or moon-looking?
Source Joel Klein
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Non-seamless pattern drawn in Paint.net and vectorised in Vector Magic.
Source Firkin