Might not be super subtle, but quite original in its form.
Source Alex Smith
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
Prismatic Floral Background No Black
Source GDJ
Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Prismatic Abstract Line Art Pattern Background 2
Source GDJ
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
Dark, square, clean and tidy. What more can you ask for?
Source Jaromír Kavan
It’s like Shine Dotted’s sister, only rotated 45 degrees.
Source mediumidee
No relation to the band, but damn it’s subtle!
Source Thomas Myrman
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin