From a drawing in 'Gately's World's Progress', Charles Beale, 1886.
Source Firkin
Just like the black maze, only in light gray. Duh.
Source Peax
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
After 1 comes 2, same but different. You get the idea.
Source Hendrik Lammers
Remixed from a drawing in 'Chambéry à la fin du XIVe siècle', Timoleon Chapperon, 1863.
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
Zero CC tileable seed texture, edited by me to be seamless from a Pixabay image. CC0
Source Sojan Janso
Honestly, who does not like a little pipe and mustache?
Source Luca Errico
Derived from a PNG that was uploaded to Pixabay by nutkitten
Source Firkin
A seamless pattern from a tile made from a jpg on Pixabay. To get the tile select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
On a large canvas you can see it tiling, but used on smaller areas, it’s beautiful.
Source Paul Phönixweiß
Zero CC tileable dry grass texture, photographed and made by me. CC0
Source Sojan Janso
This could be a hippy vintage wallpaper.
Source Tileable Patterns
Derived from an image that was uploaded to Pixabay by Darkmoon1968
Source Firkin
A seamless pattern formed from a sports car on clker.com. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Seamless pattern formed from a tile that can be had by selecting the rectangle in Inkscape and using shift-alt-i.
Source Firkin
A seamless texture of worn out "cardboard".
Source V. Hartikainen
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf