This is a continuation from my earlier post on tectonic plates.
Ice moons. They could somehow have their own atmosphere, similar to Titan, and have massive subsurface oceans underneath. This subsurface ocean would be a great resource for travellers, as it could possibly be split and used for oxygen for air to breathe and hydrogen for fuel, respectively. It could also be used as a gateway for life.
With ice moons and subsurface oceans comes the possibility for cryovolcanism. Similar to Enceladus, we could have massive geysers expelling water into space.
That's all I have to say on the topic, because my brain is dead. I'm sure you can find something else that I just haven't yet put my finger on to put in this post. I'm brain dead right now.