Easy to use app store for flatpak and apt packages
This is your classic GUI "app store", featuring screenshots, written reviews, and a one-click button to install new apps. It's geared toward desktop users and is not Raspberry Pi or ARM specific. Everything offered in it should work, and it is a good place to find easy-to-install apps that do not really need Pi-Apps to simplify the install process.

To run: Menu -> System Tools -> Discover
To run in a terminal: plasma-discover

By default, Discover will show a mix of apt packages and flatpaks, which can get pretty confusing. Also it seems to prefer apt packages, even though flatpak versions are generally newer.
To only see apt packages, run this: plasma-discover --backends packagekit
To only see flatpaks: plasma-discover --backends flatpak
