A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
From a drawing in 'Cassell's Library of English Literature', Henry Morley, 1883.
Source Firkin
A seamless background drawn in Paint.net and vectorised with Vector Magic. The starting point was a photograph of drinking straws from Pixabay.
Source Firkin
From a drawing in 'Studies for Stories', Jean Ingelow, 1864.
Source Firkin
A seamless texture traced from an image on opengameart.org shared by Scouser.
Source Firkin
Bit of a strange name on this one, but still nice. Tiny gray square things.
Source Carlos Valdez
Prismatic Abstract Geometric Background 4 No Black
Source GDJ
Vertical lines with a bumpy, yet crisp, feel to it.
Source Raasa
Super subtle indeed, a medium gray pattern with tiny dots in a grid.
Source Designova
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin
A free seamless background texture of "timber wall" (colored in dark brown).
Source V. Hartikainen
A simple circle. That’s all it takes. This one is even transparent, for those who like that.
Source Saqib
Nice little grid. Would work great as a base on top of some other patterns.
Source Arno Gregorian
From a drawing of the coat of arms of the Ottoman Empire on Wikimedia.
Source Firkin
The file was named striped lens, but hey – Translucent Fibres works too.
Source Angelica
A seamless web texture of "green stone".
Source V. Hartikainen
ZeroCC tileable stone texture, edited from pixabay, CC0
Source Sojan Janso
From a drawing in 'Two Women in the Klondike', Mary Hitchcock, 1899.
Source Firkin
A seamless texture of an abstract wall colored in shades of light orange brown.
Source V. Hartikainen
A pattern derived from repeating unit cells each derived from part of a fractal rendering in paint.net.
Source Firkin
A repeatable image with dark background and metal grid pattern.
Source V. Hartikainen
Uses spirals from Pixabay. To get the basic tile select the rectangle in Inkscape and use shift+alt+i
Source Firkin