Not so subtle. These tileable wood patterns are very useful.
Source Elemis
More bright luxury. This is a bit larger than fancy deboss, and with a bit more noise.
Source Viszt Péter
Like the name says, light and gray, with some small dots and circles.
Source Brenda Lay
Textured Red Brown Plastic, Free Background Pattern. Although there's already enough plastic in our lives, let's bring it to the web too.)
Source V. Hartikainen
This background has abstract texture with some similarities to wood.
Source V. Hartikainen
Has nothing to do with toast, but it’s nice and subtle.
Source Pippin Lee
Background formed from the original with an emboss effect
Source GDJ
Remixed from an image that was uploaded to Pixabay by KirstenStar
Source Firkin
Prismatic Geometric Pattern Background 2
Source GDJ
Sort of like the Photoshop transparent background, but better!
Source Alex Parker
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
From a drawing in 'Bond Slaves. The story of a struggle.', Isabella Varley, 1893.
Source Firkin
A seamless pale yellow paper background with a pattern of animal tracks.
Source V. Hartikainen
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
Prismatic Curved Diamond Pattern 2 No Background
Source GDJ
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A frame using leaves from an image that was uploaded to Pixabay by mayapujiati
Source Firkin
Produced using the clouds, flames and glass blocks plug-ins in Paint.net and the resulting .PNG vectorised with Vector Magic.
Source Firkin
More carbon fiber for your collections. This time in white or semi-dark gray.
Source Badhon Ebrahim