I think I’m close enough to say this with 99% certainty: every system will EVENTIALLY have an exotic ship.
I’m working on trying to see if there are any percentages by system type or other variables but, for the most part, with enough patience, you will eventually find an exotic in ANY system.
If you’re impatient, you can play the reload game.
- Go to a Trading post
- Monitor the initial ships (typically 6 to 9 ships).
- If none of them are an Exotic - reload
–repeat until the exotic shows its self.
For systems that don’t have planets with trading posts it will take a bit longer. Go to the space station and let 7 to 10 ships land before doing the reload.
I’ve gone back to 9 systems I thought would not have an exotic and 8 of them did after enough resets (so far anywhere between 2 and 56 - I’ll narrow that down in the coming week).
Regarding that one that I didn’t see an exotic: I stopped after 100 resets. I have a feeling, when I go back there, It will eventually give up its exotic.