Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Paper pattern with small dust particles and 45-degree strokes.
Source Atle Mo
By popular request, an outline version of the pentagon pattern.
Source Atle Mo
Colour version of a pattern that came out of playing with the 'light rays' plug-in for Paint.net
Source Firkin
Remixed from a drawing in 'Maidenhood; or, the Verge of the Stream', Laura Jewry, 1876.
Source Firkin
Background Wall, Art Abstract, Blue Well & CC0 texture.
Source Ractapopulous
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
An abstract texture of black metal pipes (seamless).
Source V. Hartikainen
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A seamless pattern formed from background pattern 102
Source Firkin
Zero CC tileable ground (#2) cracked, crackled texture, made by me. CC0
Source Sojan Janso
Tiny little fibers making a soft and sweet look.
Source Badhon Ebrahim
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Luxury pattern, looking like it came right out of Paris.
Source Daniel Beaton
Classic vertical lines, in all its subtlety.
Source Cody L
Dark, lines, noise, tactile. You get the drift.
Source Anatoli Nicolae
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
A seamless web texture with illustration of pale color stains on canvas.
Source V. Hartikainen
A seamless pattern formed from a sports car on clker.com. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Background formed from the original with an emboss effect.
Source Firkin
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev