Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i
Source Firkin
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
Classy golf-pants pattern, or crossed stripes if you will.
Source Will Monson
Sharp diamond pattern. A small 24x18px tile.
Source Tom Neal
Prismatic Snowflakes Pattern No Background
Source GDJ
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
Beautiful dark noise pattern with some dust and grunge.
Source Vincent Klaiber
Real snow that tiles, not easy. This is not perfect, but an attempt.
Source Atle Mo
Light square grid pattern, great for a “DIY projects” sort of website, maybe?
Source Rafael Almeida
Prismatic Snowflakes Pattern 3 No Background
Source GDJ
The tile for this is based on a repeating unit close to a design on Pixabay. It can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
Not so subtle. These tileable wood patterns are very useful.
Source Elemis
Lovely light gray floral motif with some subtle shades.
Source GraphicsWall
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
Looks like an old wall. I guess that’s it then?
Source Viahorizon
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Never out of fashion and so much hotter than the 45º everyone knows, here is a sweet 60º line pattern.
Source Atle Mo
Dark wooden pattern, given the subtle treatment. based on texture from Cloaks. https://cloaks.deviantart.com
Source Atle Mo
Classic vertical lines, in all its subtlety.
Source Cody L
Same as Silver Scales, but in black. Turn your site into a dragon with this great scale pattern.
Source Alex Parker
This one is amazing, truly original. Go use it!
Source Viahorizon
Prismatic Abstract Geometric Background 4
Source GDJ