Thanks for the reply. I operate therpgpipeline.com which posts all the new standalone ttrpgs as they come out. I posted about 2,400 new games last year and I'm looking to help users get their head around the new stuff in the year and point them towards the games that were more significant (this is a tough to measure but I was considering best sellers as the more people who own the game the more likely it is to get played as you typically need 3-6 players to play a ttrpg). 

I've subscribed to the Physical Product Best Sellers RSS thinking I could track games as they're added but as far as I could tell all the games get added to that RSS so that the itch algo can then do its ranking.

Sales aren't the be-all and end-all, I'm just looking for some quantitative way to say 'Of the games released in 2019, look at these 10' for example.