A command for players to see a list of parties with more than one member (/openpac-parties list)

Please explain why you need that.

I think it would be cool to see who the biggest parties are on the server

Hmm. In that case you definitely want the output to be sorted. There is an issue with that. The number of parties is not really limited. Sorting a million parties for such a list is not an easy job. It probably won't be 100% accurate either if I optimize it to where it's usable. This won't be a problem for a vast majority of servers but I want this mod to work on as many servers as possible.
I need to think about this more.

Although a million parties is very extreme and will likely cause issues elsewhere to begin with. That's why there is party expiration. Adding this command is probably not that big of a problem, I just need to be careful about it.