This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
One more brick pattern. A bit more depth to this one.
Source Benjamin Ward
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Prismatic Hypnotic Pattern No Background
Source GDJ
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
Prismatic Curved Diamond Pattern No Background
Source GDJ
Sort of reminds me of those old house wallpapers.
Source Tish
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
Remixed from a raster on Pixabay, that was uploaded by ArtsyBee.
Source Firkin
A comeback for you: the popular Escheresque, now in black.
Source Patten
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
This is a remix of "blue wave-seigaiha".I hope this subtle color version of Seigaiha would be suitable for background .
Source Yamachem
The image depicts a seamless pattern of a Japanese family crest called "chidori" in Japanese .A chidori in Japanese means a plover in English.
Source Yamachem
This tiled background comes in red and consists of tiles that look like gemstones. It is more for blogs or social profiles, I think.
Source V. Hartikainen
Looks as if it's spray painted on the wall. You can be sure that this pattern will seamlessly fill your backgrounds on web pages.
Source V. Hartikainen
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
Heavily remixed from a drawing in 'Barbara Leybourne; a story of eighty years ago', Sarah Hamer, 1889.
Source Firkin
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin