Wondering what goes on in the iOS App Store? Obviously you're not the only one, because Sensor Tower has published a visualization of everything in the App Store, divided and color-coded by category - books, entertainment, games, and so on - and complete with filters to view only the categories in which you are interested.
For each category, the graph can be adjusted up and down various axes, such as ratings, reviews, estimated downloads, and more, and sample apps in close proximity to the average line will be generated. Or, you can also look up individual apps for a graph of their stats in all of these categories.
The whole thing was put together using the Parallel Coordinates technique and d3.js, and it's a treasure-trove of information for any mobile developer, iOS or otherwise. Check it out for a look at what, exactly, the iOS App Store is full of, and more importantly, what makes it all tick.