Planetsim is a spin-off oriented around anything space. It was (likely) the first real spin-off to come from the countrysim community, started around April of 2018. It's latest spike in activity occured around early 2024.
Worldsim used a real world map for the territories that people would be allowed to own. It has gone through multiple iterations, and is currently inactive.
Europesim used a real world map specifically of Europe. It was mainly active in early 2021.
---other sims to be added---
Countrysim