A bit of scratched up grayness. Always good.
Source Dmitry
A repeating gloomy background image. This one consists of a pattern of black chains layered on top of a dark textured background.
Source V. Hartikainen
Has nothing to do with toast, but it’s nice and subtle.
Source Pippin Lee
Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
Sometimes you just need the simplest thing.
Source Fabricio
Derived from elements found in a floral ornament drawing on Pixabay.
Source Firkin
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
If you want png files of this u can download them here : viscious-speed.deviantart.com/gallery/27635117
Source Viscious-Speed
This background pattern has futuristic look. So, maybe it could be used on websites or blogs dedicated to video games?!
Source V. Hartikainen
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
All good things come in threes, so I give you the third in my little concrete wall series.
Source Atle Mo
Scanned some rice paper and tiled it up for you. Enjoy.
Source Atle Mo
Prismatic Abstract Geometric Background 2
Source GDJ
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
Prismatic Isometric Cube Wireframe Pattern No Background
Source GDJ
A floral background formed from numerous clones of flower 117.
Source Firkin
From a drawing in 'Sun Pictures of the Norfolk Broads', Ernest Suffling, 1892.
Source Firkin
Inspired by a pattern seen on a public domain image of a very old tile. To get the unit cell, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua