Might not be super subtle, but quite original in its form.
Source Alex Smith
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Otis Ray Redding was an American soul singer-songwriter, record producer, arranger, and talent scout. So you know.
Source Thomas Myrman
Light gray version of the Binding pattern that looks a bit like fabric.
Source Newbury
ZeroCC tileable stone texture, edited from pixabay, CC0
Source Sojan Janso
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
Don’t look at this one too long if you’re high on something.
Source Luuk van Baars
Prismatic Groovy Concentric Background
Source GDJ
The image depicts meshed silhouettes of various things.The original image is an OCAL clipart called "Enter FOSSASIA 2016 #IoT T-shirt Design Contest" uploaded by "openclipart".Thanks.
Source Yamachem
From a drawing of the coat of arms of the Ottoman Empire on Wikimedia.
Source Firkin
Remixed from an image on Pixabay uploaded by Prawny
Source Firkin
Fix and cc0 to get the tile this is based on.
Source SliverKnight
Zero CC tileable Crackled Cement (streaks) texture, photographed and made by me. CC0
Source Sojan Janso
Formed from decorative divider 184 in paint.net. Vectorised with Vector Magic.
Source Firkin
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A background pattern inspired by designs seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Inspired by this, I came up with this pattern. Madness!
Source Atle Mo
Based on an image that was uploaded to Pixabay by devanath
Source Firkin
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ