A comeback for you: the popular Escheresque, now in black.
Source Patten
Derived from an image that was uploaded to Pixabay by Kaz
Source Firkin
Prismatic Hexagonalism Pattern No Background
Source GDJ
Colour version of the original pattern inspired by the front cover of 'Old and New Paris', Henry Edwards, 1894.
Source Firkin
A large pattern with funky shapes and form. An original. Sort of origami-ish.
Source Luuk van Baars
Utilising some flowers from Almeidah. To get the unit tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Can never have too many knitting patterns, especially as nice as this.
Source Victoria Spahn
A very slick dark rubber grip pattern, sort of like the grip on a camera.
Source Sinisha
A pattern drawn in Paint.net and vectorized in Vector Magic.
Source Firkin
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
Lovely pattern with some good-looking non-random noise lines.
Source Zucx
Number 5 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Love me some light mesh on a Monday. Sharp.
Source Wilmotte Bastien
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A series of 5 patterns. That’s what the P stands for, if you didn’t guess it.
Source Dima Shiper
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
Floral patterns might not be the hottest thing right now, but you never know when you need it!
Source Lauren
From a drawing in 'Handbook of the excursions proposed to be made by the Lincoln Diocesan Architectural Society, on the 27th and 28th of May, 1857', Edward Trollope, 1857.
Source Firkin
From a drawing in 'Navigations de Alouys de Cademoste.-La Navigation du Capitaine Pierre Sintre', Alvise da ca da Mosto, 1895.
Source Firkin
ZeroCC tileable wood boards texture, photographed and made by me. CC0
Source Sojan Janso
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett