From a drawing in 'Les Chroniqueurs de l'Histoire de France depuis les origines jusqu'au XVIe siècle', Henriette Witt, 1884.
Source Firkin
Sounds French. Some 3D square diagonals, that’s all you need to know.
Source Graphiste
As far as fabric patterns goes, this is quite crisp.
Source Heliodor Jalba
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
Remixed from a drawing in 'Paul's Sister', Frances Peard, 1889.
Source Firkin
A floral background formed from numerous clones of flower 117.
Source Firkin
Smooth Polaroid pattern with a light blue tint.
Source Daniel Beaton
Prismatic Groovy Concentric Background 5
Source GDJ
From a drawing in 'At home', J. Sowerby, J. Crane and T. Frederick, 1881.
Source Firkin
From a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
From a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
A nice and simple gray stucco material. Great on its own, or as a base for a new pattern.
Source Bartosz Kaszubowski
Dark blue concrete wall with some small dust spots.
Source Atle Mo
The green fibers pattern will work very well in grayscale as well.
Source Matteo Di Capua
This is a seamless pattern which is derived from a flower petal image.
Source Yamachem
Prismatic Curved Diamond Pattern 8 No Background
Source GDJ
Different from the original in being a simple tile stored as a pattern definition, rather than numerous repeated objects. Hence easy and quick to give this pattern to objects of different shapes. To get the tile in Inkscape, select the rectangle and use shift+alt+i.
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
And some more testing, this time with Seamless Studio. It’s Robots FFS!
Source Seamless Studio
Colour version of the original pattern inspired by the front cover of 'Old and New Paris', Henry Edwards, 1894.
Source Firkin
Derived from an image that was uploaded to Pixabay by starchim01
Source Firkin
An abstract texture of water. It's not perfect, but will do. You may download if you like it.
Source V. Hartikainen
To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i
Source Firkin
A repeating background of beige paper with vintage look. Repeats to infinity, as usual.
Source V. Hartikainen