This is so subtle you need to bring your magnifier!
Source Carlos Valdez
Inspired by a design found in 'Konstantinápolyi emlékeim', Miklos Chriszto, 1893.
Source Firkin
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
Prismatic Polka Dots Mark II 3 No Background
Source GDJ
Remixed from a raster on Pixabay that was uploaded by ArtsyBee.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
A seamless pattern formed from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Prismatic Snowflakes Pattern 2 No Background
Source GDJ
Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
We have some linen patterns here, but none that are stressed. Until now.
Source Jordan Pittman
Continuing the geometric trend, here is one more.
Source Mike Warner
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
Zero CC tileable cork floor, photographed and made by me. CC0
Source Sojan Janso
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
A seamless texture of black leather. I think it will look best when used in headers, footers or sidebars.
Source V. Hartikainen
Might not be super subtle, but quite original in its form.
Source Alex Smith
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
We have some linen patterns here, but none that are stressed. Until now.
Source Jordan Pittman
Prismatic Abstract Geometric Background 5
Source GDJ
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
It looks very nice I think.
Source V. Hartikainen
Vector version of a png that was uploaded to Pixabay by pencilparker
Source Firkin
Used the 6th circle pattern designed by Viscious-Speed to create a print that can be used for card making or scrapbooking. Save as a PDF file for the best printing option.
Source Lovinglf