A topographic map like this has actually been requested a few times, so here you go!
Source Sam Feyaerts
This is a hot one. Small, sharp and unique.
Source GraphicsWall
Just like the black maze, only in light gray. Duh.
Source Peax
This is so subtle you need to bring your magnifier!
Source Carlos Valdez
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
Looks like an old wall. I guess that’s it then?
Source Viahorizon
A seamless pattern from a tile drawn in Paint.net and vectorised in Vector Magic
Source Firkin
Nicely crafted paper pattern, although a bit on the large side (500x593px).
Source Blaq Annabiosis
Remixed from a design on Pixabay. To get the tile this is based on 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
Not strictly seamless in that opposite edges are not identical. But they do marry up to make an interesting pattern
Source Firkin
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Small gradient crosses inside 45-degree boxes, or bigger crosses if you will.
Source Wassim
A seamless pattern the starting point for which was a 'rainbow twist' texture in Paint.net.
Source Firkin
It’s like Shine Dotted’s sister, only rotated 45 degrees.
Source mediumidee
The base gradient edited so now more details are rendered.
Source Lazur URH
Remixed from a drawing in 'Works. Popular edition', John Ruskin, 1886.
Source Firkin