Not a flat you live inside, like in the UK – but a flat piece of cardboard.
Source Appleshadow
A lovely light gray pattern with stripes and a dash of noise.
Source V. Hartikainen
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
This one could be the shirt of a golf player. Angled lines in different thicknesses.
Source Olivier Pineda
A seamless pattern formed from miutopia's cakes on a tablecloth.
Source Firkin
Dark blue concrete wall with some small dust spots.
Source Atle Mo
With a name this awesome, how can I go wrong?
Source Nikolay Boltachev
Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857.
Source Firkin
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
I guess this is inspired by the city of Ravenna in Italy and its stone walls.
Source Sentel
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
One of the few full-color patterns here, but this one was just too good to pass up.
Source Alexey Usoltsev
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Remixed from a drawing in 'Очерки Русской Исторіи въ памятникахъ быта', Petr Polevoi, 1879.
Source Firkin
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
The tile this is formed from can be retrieved in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin