Numista can now show the results of auctions for coins and banknotes in the catalogue.
See this aureus from Brutus for example. You can see at the bottom that one of these aurei was sold for 2.7 million GBP in October 2020, with a link to the details of this lot on Roma Numismatics' website.
The idea is to show more samples and to give an idea of the price for less common coins and banknotes.
Like the rest of the content of the catalogue, this is a collaborative feature: click on "Register a past auction sale" at the bottom of the page of the coin type or banknote type. Requests to register a sale will be approved by referees before the sale becomes visible.
I hope you like it!
PS: The similar feature "Match past online sales" which allowed to map auctions from eBay will probably disappear soon. It's already partly broken, as eBay closed the access to retrieve their past sales a few months ago.