Nauvis, Vulcanus, Fulgora, Gleba, and planet 5. I think that's all of them, just the far dark planet we haven't seen yet.

I think new enemies are on the known planets as well, we just haven't been introduced yet. Probably Gleba will have enemies. I'm terrified of what could survive on Vulcanus and Fulgora, maybe defence robots? And what biosphere could exists on a dark rock? Maybe whatever caused the Fulgora civilization to collapse?