Sometimes you just need the simplest thing.
Source Fabricio
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
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
A hint of orange color, and some crossed and embossed lines.
Source Adam Anlauf
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Prismatic Abstract Geometric Background 3
Source GDJ
This was formed by distorting an image of a background on Pixabay.
Source Firkin
This is sort of fresh, but still feels a bit old school.
Source Martuchox
A pale olive green background with a seamless texture.
Source V. Hartikainen
Pattern #100! A black classic knit-looking pattern.
Source Factorio.us Collective
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Prismatic Groovy Concentric Background 5 No Black
Source GDJ
To get the tile this is based on select the rectangle in Inkscape and use shift-alt-i
Source Firkin
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
Continuing the geometric trend, here is one more.
Source Mike Warner
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
From a drawing in 'The Quiver of Love', Walter Crane, 1876
Source Firkin
From a design found in 'History of the Virginia Company of London; with letters to and from the first Colony, never before printed', Edward Neill, 1869.
Source Firkin
Prismatic Floral Background No Black
Source GDJ
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
A seamless background pattern with impressed gray dots.
Source V. Hartikainen
Adapted heavily from a JPG that was uploaded to Pixabay by Viscious-Speed.
Source Firkin