Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Redrawn based on a drawing in 'По Сѣверо-Западу Россіи' Konstantin Sluchevsky, 1897.
Source Firkin
Tweed is back in style – you heard it here first. Also, the @2X version here is great!
Source Simon Leo
Psychedelic Geometric Background No Black
Source GDJ
Sharp pixel pattern looking like some sort of fabric.
Source Dmitry
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
From a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
Used correctly, this could be nice. Used in a bad way, all hell will break loose.
Source Atle Mo
Use shift+alt+i on the selected rectangle in Inkscape to get the tile this is based on
Source Firkin
Crossing lines with a subtle emboss effect on a dark background.
Source Stefan Aleksić
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
Looks a bit like concrete with subtle specks spread around the pattern.
Source Mladjan Antic
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
From a drawing in 'A Rolling Stone. A tale of wrongs and revenge', John Hartley, 1878.
Source Firkin
An alternative colour scheme for the original background.
Source Firkin
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
More leather, and this time it’s bigger! You know, in case you need that.
Source Elemis
This one could be the shirt of a golf player. Angled lines in different thicknesses.
Source Olivier Pineda