Not so subtle. These tileable wood patterns are very useful.
Source Elemis
From a drawing in 'Royal Ramsgate', James Simson, 1897.
Source Firkin
This is a seamless pattern of regular hexagon which has a honeycomb structure.
Source Yamachem
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
Remixed from a drawing in 'Hungary. A guide book. By several authors', 1890.
Source Firkin
Bright Multicolored Floral Background by Karen Arnold from PDP.
Source GDJ
You know I’m a sucker for these. Well-crafted paper pattern.
Source Mihaela Hinayon
A seamless pattern the starting point for which was a 'light rays' rendering in Paint.net.
Source Firkin
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A fun-looking elastoplast/band-aid pattern. A hint of orange tone in this one.
Source Josh Green
Light honeycomb pattern made up of the classic hexagon shape.
Source Federica Pelzel
This ons is quite old school looking. Retro, even. I like it.
Source Arno Declercq
The image depicts a seamless pattern of a fishnet with a plenty of fish.It may be a lucky charm for fishermen.
Source Yamachem
Prismatic Rounded Squares Grid 3 No Background
Source GDJ
Green Web Background, Seamless tile.
Source V. Hartikainen
This is lovely, just the right amount of subtle noise, lines and textures.
Source Richard Tabor
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
Zero CC tileable brick texture, photographed and made by me. CC0
Source Sojan Janso
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