From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
Thin lines, noise and texture creates this crisp dark denim pattern.
Source Marco Slooten
Zero CC tileable moss or lichen covered stone texture, edited from pixabay. CC0
Source Sojan Janso
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
Prismatic Curved Diamond Pattern No Background
Source GDJ
This is so subtle: We’re talking 1% opacity. Get your squint on!
Source Atle Mo
Semi-light fabric pattern made out of random pixels in shades of gray.
Source Atle Mo
More Japanese-inspired patterns, Gold Scales this time.
Source Josh Green
The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
A browner version of the original weathered fence texture.
Source Firkin
Seamless Light Background Texture.
Source V. Hartikainen
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Remixed from a drawing in 'The March of Loyalty', Letitia MacClintock, 1884.
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A dark metallic background with a pattern of stamped dots. Here's a dark "metallic" background pattern for you.
Source V. Hartikainen
An emulated “transparent” background pattern, like that of all kinds of computer graphics software.
Source AdamStanislav