This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
Some rectangles, a bit of dust and grunge, plus a hint of concrete.
Source Atle Mo
The first pattern on here using opacity. Try it on a site with a colored background, or even using mixed colors.
Source Nathan Spady
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Background Wall, Art Abstract, Block Well & CC0 texture.
Source Ractapopulous
I’m guessing this is related to the Sony Vaio? It’s a nice pattern no matter where it’s from.
Source Zigzain
From a drawing in 'In an Enchanted Island', William Mallock, 1892.
Source Firkin
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
Colour version that is close to the original drawing uploaded to Pixabay by pencilparker.
Source Firkin
Abstract Geometric Monochrome Pattern Prismatic No Background
Source GDJ
Zero CC tileable seed texture, edited by me to be seamless from a Pixabay image. CC0
Source Sojan Janso
Inspired by a pattern found in 'A General History of Hampshire, or the County of Southampton, including the Isle of Wight', Bernard Woodwood, 1861
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A white version of the very popular linen pattern.
Source Ant Ekşiler
This metal background pattern resembles a metal plate with rivets. Solid rivets on a metal plate.
Source V. Hartikainen
A comeback for you: the popular Escheresque, now in black.
Source Patten
As simple and subtle as it gets. But sometimes that’s just what you want.
Source Designova