If you like it a bit trippy, this wave pattern might be for you.
Source Ian Soper
This one takes you back to math class. Classic mathematic board underlay.
Source Josh Green
The tile can be had by selecting the rectangle in Inkscape and using shift+alt+i. Remixed from a drawing in 'Flowers of Song', Frederick Weatherly, 1895.
Source Firkin
A seamlessly tile-able grunge background image.
Source V. Hartikainen
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
This could be a hippy vintage wallpaper.
Source Tileable Patterns
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Has nothing to do with toast, but it’s nice and subtle.
Source Pippin Lee
This one is so simple, yet so good. And you know it. Has to be in the collection.
Source Gluszczenko
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
The image depicts a seamless pattern made using a bird's face.
Source Yamachem
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
Remixed from a drawing in 'Canadian forest industries July-December', 1915
Source Firkin
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
This is so subtle I hope you can see it! Tweak at will.
Source Alexandre Naud
Simple wide squares with a small indent. Fits all.
Source Petr Šulc.
A bit strange this one, but nice at the same time.
Source Diogo Silva
Prismatic Groovy Concentric Background No Black
Source GDJ
A monochrome pattern from a tile that can be had by selecting the rectangle in Inkscaope and using shift+alt+i
Source Firkin
Did some testing with Repper Pro tonight, and this gray mid-tone pattern came out.
Source Atle Mo
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin