Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
This one is rather fun and playful. The 2X could be used at 1X too!
Source Welsley
Simple gray checkered lines, in light tones.
Source Radosław Rzepecki
Super dark, crisp and detailed. And a Kill Bill reference.
Source Badhon Ebrahim
Background formed from the original with an emboss effect
Source GDJ
From a drawing in 'Uit de geschiedenis der Heilige Stede te Amsterdam', Yohannes Sterck, 1898.
Source Firkin
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
A background tile for web with abstract repeating texture of dark "stone wall".
Source V. Hartikainen
Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
Got some felt in my mailbox today, so I scanned it for you to use.
Source Atle Mo
The starting point for this was drawn on the web site steamcoded.org/PolyskelionMaker.svg
Source Firkin
From a drawing in 'Cowdray: the history of a great English House', Julia Roundell, 1884.
Source Firkin
Cubes as far as your eyes can see. You know, because they tile.
Source Jan Meeus
With a name like this, it has to be hot. Diagonal lines in light shades.
Source Isaac
It’s a hole, in a pattern. On your website. Dig it!
Source Josh Green
This background image is great for using in web design or graphic design projects. And don't forget to visit the homepage. I frequently update this resource with fresh tileable backgrounds.
Source V. Hartikainen
Remixed from an image that was uploaded to Pixabay by Pixeline
Source Firkin
An abstract Background pattern of purple twisty patterns.
Source TikiGiki
Design drawn in Paint.net, vectorised using Vector Magic and finished in Inkscape.
Source Firkin
From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
A seamless chequerboard pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i. Alternative colour scheme.
Source Firkin
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin