Additionally, the accuracy of the number of downloads might vary wildly between marketplaces, because they all have different reporting standards, don't they?
Also, I would sort them by popularity with the most popular ones at the top. A first-time visitor is going to be very confused seeing "3DS Max" and "After Effects Plugins". You should probably have the more common ones at the top: iOS App Store, Mac App Store, Play Store, Microsoft Store, etc...
Cool idea.
Do these marketplaces actually publish total number of dev/apps or are you crawling them to get an approximation?
The following article claims there are only 2.1 million apps in the iOS app store. How did you get your number of 3.2 million?
https://www.lifewire.com/how-many-apps-in-app-store-2000252
Additionally, the accuracy of the number of downloads might vary wildly between marketplaces, because they all have different reporting standards, don't they?
Also, I would sort them by popularity with the most popular ones at the top. A first-time visitor is going to be very confused seeing "3DS Max" and "After Effects Plugins". You should probably have the more common ones at the top: iOS App Store, Mac App Store, Play Store, Microsoft Store, etc...