Stellaris Mod: Life Engineering Planetary Preserves
Using the awesome life engineering mod, you can create a series of preserves and then do very good or bad things to the inhabitants of the planet.
You can:
Deny Technological Advancement
Accelerate their societal development
Release Mutagens
Demand your friends and allies send pops to the world
Or even organize away teams to the surface.
The RP potential is endless.