Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Prismatic Abstract Geometric Background 2
Source GDJ
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
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
Remixed from a drawing that was uploaded to Pixabay by ractapopulous
Source Firkin
Seamless Background For Websites. It has a texture similar to cork-board.
Source V. Hartikainen
Prismatic Isometric Cube Extra Pattern No Background
Source GDJ
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
One more sharp little tile for you. Subtle circles this time.
Source Blunia
White circles connecting on a light gray background.
Source Mark Collins
Here's an yet another background for websites, with a seamless texture of wood planks this time.
Source V. Hartikainen
This ladies and gentlemen, is texturetastic! Love it.
Source Adam Pickering
A seamless pattern formed from a square tile. The tile can be retrieved 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
Seamless pattern formed from a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
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
Number five from the same submitter, makes my job easy.
Source Dima Shiper
Has nothing to do with toast, but it’s nice and subtle.
Source Pippin Lee
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Another fairly simple design drawn in Paint.net and vectorized in Inkscape.
Source Firkin
From a drawing in 'Codogno e il suo territorio nella cronaca e nella storia'', Gio and Giarella Cairo, 1897.
Source Firkin