I added "unvisited" as a command to select a random planet from the set of known "public" planets that you have not yet visited. You can specify a difficulty range.
I considered making it a goal, rather than a command, but it's not actually something you are looking for; it's a way to start from a different list of planets.
On the other hand, if it WERE a goal, you could say "unvisited, space baby", for example.
I'm torn, but my intended use is in place of "random" - i.e., I don't want to always select the hardest, as is done with goals - so I'll leave it as this for now.
Revision 166. That also detects spreadsheet planets that claim to have more than one kind of ancient ruins and treats that as simply "detected".
Thanks for this, I'm still using the GingerBread script daily and I'm going to see if this'll get me the primitive alien drops.