Just some suggestions to add to the game! Add yours

Gas giants – cannot land on them, but you can mine gas / valuables using a frigate

Quasars/Pulsars – high gravity anomalies which have valuable resources, however if your ship isn’t up for the challenge or you get too close you get pulled in and crushed

Mass extinction events – huge planet wiping meteors you have to destroy before they reach a planet (your base or settlement location)

Terraforming – turn hellish worlds into the perfect home, this may look different depending on which races technologies are used

Auroras – different colours patterns of the “northern lights” occur at the poles, depending on type of atmosphere and star

Tornadoes/Earthquakes/Tsunamis – and planets which have weird behaviours (like the giant wave planet in Interstellar)

Multiple biomes on single planets – the poles are cold and the equator is hot right?

Subterranean worlds – for example an Ice planet which has a whole different ecosystem under a thick layer of ice (good chance to expand on underwater bases) A la that Ice Age film where Simon Pegg plays a weasel

Comets – are you skilled enough to land on them and mine the rewards?