Find a file in the Finder that you’d like to try this on, and either right-click or Control-click on it to bring up the contextual menu. Choose “Open With,” and then if you look at the bottom of the list of potential applications, you’ll see the “App Store” option.
Clicking on that opens the App Store (shocking, I know). However, the cool thing to note is that doing so will show you a selection of programs that the App Store thinks you can use for that file type. You can see in my screenshot below that it performed a search by “uti:public.plain-text” for the TextEdit document I chose. UTIs (Uniform Type Identifiers) are essentially Apple’s way of categorizing types of files; Spotlight, for example, uses this same technology.
So if you have a particular file kind that you work with often, it’s probably worth your time to see what the App Store offers for those types of documents. And if you’d like to learn more about how to take advantage of Spotlight’s ability to recognize categories, check out this awesome tip from Jeff Gamet.