Might not be super subtle, but quite original in its form.
Source Alex Smith
Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A free seamless background image with a texture of dark red "canvas". It should look very nice on web sites.
Source V. Hartikainen
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
A simple circle. That’s all it takes. This one is even transparent, for those who like that.
Source Saqib
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
A huge one at 800x600px. Made from a photo I took going home after work.
Source Atle Mo
Tile available in Inkscape using shift-alt-i on the selected rectangle
Source Firkin
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
A seamless pattern with green and yellow diagonal lines on top of a white dotted background.
Source V. Hartikainen
Sharp but soft triangles in light shades of gray.
Source Pixeden
You were craving more leather, so I whipped this up by scanning a leather jacket.
Source Atle Mo
The original enhanced with one of Inkscapes's filters.
Source Firkin
Here's a camo print with more tan and less green, such as might be used in a desert scenario. This is tileable, so it can be used as a wallpaper or background.
Source Eady
A free tileable background colored in off-white (antique white) color.
Source V. Hartikainen
From a drawing in 'Resa i Afrika, genom Angola, Ovampo och Damaraland', P. Moller, 1899.
Source Firkin
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'Heroes of North African Discovery', Nancy Meugens, 1894.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
Feel free to use this seamless background texture as a background on a web site. It's colored in a light pink color and is seamlessly tile-able.
Source V. Hartikainen
Sort of like the Photoshop transparent background, but better!
Source Alex Parker