it only shows a portion of the apps in a given category. Even if you click on the see more in the subcategories some apps are not listed. For example, I can't find Lightroom Mobile in the photos and videos category.
You can do that on a website like AppShopper, but they don't let you directly do that on the App Store. The closest you can get is looking through the top charts and changing the category there and you'll see the top 150 in Paid & Free.