Not so subtle. These tileable wood patterns are very useful.
Source Elemis
A seamless pale yellow paper background with a pattern of animal tracks.
Source V. Hartikainen
Remixed from a JPG that was uploaded to Pixabay by susanlu4esm
Source Firkin
Colour version of the original pattern.
Source Firkin
Subtle scratches on a light gray background.
Source Andrey Ovcharov
Dead simple but beautiful horizontal line pattern.
Source Fabian Schultz
The image a seamless pattern derived from a weed which I can't identify.The original weed image is from here:https://jp.pinterest.com/pin/500744052301423641/
Source Yamachem
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This is indeed a bit strange, but here’s to the crazy ones!
Source Christopher Buecheler
Prismatic Polka Dots Mark II No Background
Source GDJ
Remixed from a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
A light gray fabric pattern with faded vertical stripes.
Source V. Hartikainen
Colourful background achieved with gradient fills.
Source Firkin
Submitted in a cream color, but you know how I like it.
Source Devin Holmes
Drawn in Paint.net and vectorised in Vector Magic.
Source Firkin
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
Zero CC tileable cork floor, photographed and made by me. CC0
Source Sojan Janso
Tile available in Inkscape using shift-alt-i on the selected rectangle
Source Firkin
A slightly more textured pattern, medium gray. A bit like a potato sack?
Source Bilal Ketab
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
He influenced us all. “Don’t be sad because it’s over. Smile because it happened.”
Source Atle Mo
A free seamless background with pink spots.
Source V. Hartikainen