Some more diagonal lines and noise, because you know you want it.
Source Atle Mo
Might not be super subtle, but quite original in its form.
Source Alex Smith
A bit of scratched up grayness. Always good.
Source Dmitry
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
You may use it as is, or modify it as you like.
Source V. Hartikainen
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
A seamless web texture of "green stone".
Source V. Hartikainen
A seamless texture of an abstract wall colored in shades of light orange brown.
Source V. Hartikainen
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
A seamless pattern formed from a tile made from ornament 22. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Abstract Geometric Background 2 No Black
Source GDJ
Prismatic Geometric Tessellation Pattern 4 No Background
Source GDJ
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
Zero CC Mossy stone tileable texture, photographed and made by me. CC0
Source Sojan Janso
Not sure if this is related to the Nami you get in Google image search, but hey, it’s nice!
Source Dertig Media
More bright luxury. This is a bit larger than fancy deboss, and with a bit more noise.
Source Viszt Péter
This seamless background image should look nice on websites. It has a dark blue gray texture with vertical stripes, it tiles seamlessly and, like all of the background images here, it's free. So, if you like it, take it!
Source V. Hartikainen
Prismatic Hypnotic Pattern 2 No Background
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
A nice and simple gray stucco material. Great on its own, or as a base for a new pattern.
Source Bartosz Kaszubowski
Prismatic Triangular Seamless Pattern III With Background
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin