Might not be super subtle, but quite original in its form.
Source Alex Smith
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
ZeroCC tileable mossy (lichen) stone texture, edited from pixabay. CC0
Source Sojan Janso
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
From a drawing in 'Artists and Arabs', Henry Blackburn, 1868
Source Firkin
Prismatic Curved Diamond Pattern 5 No Background
Source GDJ
This was formed by distorting an image of a background on Pixabay.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
The name tells you it has curves. Oh yes, it does!
Source Peter Chon
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Hexagonal dark 3D pattern. What more can you ask for?
Source Norbert Levajsics
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
Has nothing to do with toast, but it’s nice and subtle.
Source Pippin Lee
Prismatic Curved Diamond Pattern 4 No Background
Source GDJ
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
More leather, and this time it’s bigger! You know, in case you need that.
Source Elemis
A brown seamless wood texture in a form of stripe pattern. The result has turned out pretty well, in my opinion.
Source V. Hartikainen
A rusty grunge background for websites. Feel free to use it in your site's theme.
Source V. Hartikainen
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