The first uncommon planet is Zeta.
The second common planet is an Eta.
I have a total of 7 planets. In my opinion, this is a good achievement.
To make it easier to find the planets you need to know the logic of the distribution of planets in space. While it is difficult for me to say exact algorithms, but approximately I can understand in which area of space they are easier to discovering.
Also, I can't deny that I'm just lucky.