I think it would be really useful to add a new filter to the search to filter by Numista Rarity Index. Something like this:
Numista Rarity Index: from [. ] to [. ]
this would be useful for finding common types we are missing, rare coins that you‘d want to exclude from the search, etc.
For example I’m looking to get the very common coins i’m missing from Spain, so I put in the filter [0] to [5]. then I can find the coins and swap for them easily.