Might not be super subtle, but quite original in its form.
Source Alex Smith
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Otis Ray Redding was an American soul singer-songwriter, record producer, arranger, and talent scout. So you know.
Source Thomas Myrman
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
Here's a brown background pattern with subtle stripes. I hope you'll like the color. If not, feel free to change it using an image editor, if you know how of course. Personally, I'm using GIMP to create these backgrounds.
Source V. Hartikainen
Sharp pixel pattern, just like the good old days.
Source Paridhi
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
A free seamless background with pink spots.
Source V. Hartikainen
Original seamless pattern with an Inkscape filter.
Source Firkin
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
Number five from the same submitter, makes my job easy.
Source Dima Shiper
A seamless pattern of leopard skin. It should look nice as a background element on web pages.
Source V. Hartikainen
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The rectangular tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A textured orange background pattern with vertical stripes.
Source V. Hartikainen
A nice and simple white rotated tile pattern.
Source Another One
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
A light gray wall or floor (you decide) of concrete.
Source Atle Mo
I’m not going to lie – if you submit something with the words Norwegian and Rose in it, it’s likely I’ll publish it.
Source Fredrik Scheide
I took the liberty of using Dmitry’s pattern and made a version without perforation.
Source Atle Mo
Background formed from the iconic plastic construction bricks that gave me endless hours of fun when I was a lad.
Source Firkin
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
In the spirit of WWDC 2011, here is a dark iOS inspired linen pattern.
Source Atle Mo