Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo
A seamless web texture with illustration of pale color stains on canvas.
Source V. Hartikainen
This one is amazing, truly original. Go use it!
Source Viahorizon
Sounds like something from World of Warcraft. Has to be good.
Source Tony Kinard
A seamless background pattern of dark brown wood planks.
Source V. Hartikainen
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
Remixed from a raster on Pixabay, that was uploaded by ArtsyBee.
Source Firkin
Seamless Background For Websites. It has a texture similar to cork-board.
Source V. Hartikainen
Continuing the geometric trend, here is one more.
Source Mike Warner
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
Dark Tile-able Grunge Texture. I think this texture can be classified as grunge. It's free and seamless, as always.
Source V. Hartikainen
From a drawing in 'Danmarks Riges Historie af J. Steenstrup, Kr. Erslev, A. Heise, V. Mollerup, J. A. Fridericia, E. Holm, A. D. Jørgensen', 1897.
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
Prismatic Snowflakes Pattern No Background
Source GDJ
Remixed from a drawing in 'A Child of the Age', Francis Adams, 1894.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
Retro Circles Background 8 No Black
Source GDJ
Super detailed 16×16 tile that forms a beautiful pattern of straws.
Source Pavel
Remixed from a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Might not be super subtle, but quite original in its form.
Source Alex Smith
Abstract Tiled Background Extended 12
Source GDJ
Prismatic Groovy Concentric Background 5
Source GDJ
Drawn in Paint.net using the kaleidoscope plug-in and vectorised.
Source Firkin