A comeback for you: the popular Escheresque, now in black.
Source Patten
This makes me wanna shoot some pool! Sweet green pool table pattern.
Source Caveman
To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Remixed from a design seen on Pixabay. The basic tile can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Number 1 in a series of 5 beautiful patterns. Can be found in colors on the submitter’s website.
Source Janos Koos
Here I have tried to create something that would look like maple wood. Not sure how well it's turned out, but at least it looks like wood.
Source V. Hartikainen
Clean and crisp lines all over the place. Wrap it up with this one.
Source Dax Kieran
Zero CC tileable dry grass texture, photographed and made by me. CC0
Source Sojan Janso
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
The name alone is awesome, but so is this sweet dark pattern.
Source Federica Pelzel
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
Bumps, highlight and shadows – all good things.
Source Badhon Ebrahim
Light gray paper pattern with small traces of fiber and some dust.
Source Atle Mo
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
A seamless pattern based on a square tile that can be retrieved in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Not the Rebel alliance, but a dark textured pattern.
Source Hendrik Lammers
Drawn in Paint.net and vectorised in Vector Magic
Source Firkin