Advanced Search in Google Play Store?

Hi there, im conducting research on a wast amount of different VPN applications, and doing so I would like to gather some statistics on how many applications there are based om my criteria. Is there any good way of doing this nowadays? I found one app called App Finder, which has a bit more freedom that the Play Store, but doesn't quite hit the mark. I want to be able to for example see, how many apps there are based on a certain term like, "VPN".

Any pin pointers towards this are greatly appreciated :)