I´m wondering if there is a inventory of the apps which are available in the teams store anywhere? If you want to restrict the apps which are available in Teams it´s hard to find out which apps are new/available.
Also to assess the apps a inventory & list which you can access programmatically would be cool (idealy via PS).
I would recommend the Apps Inventory in the 365 admin panel under settings > services and add ins. This is also where you control what apps appear in Teams. Hopefully, this should be moved into the Teams and Skype control panel in the future.