How to get a list of all apps in the flatpak usb drive

Iam new to flatpak,
I made a flatpak usb-drive that contains a bunch of frequent apps i use in regular,
I want to know what apps are in the flatpak drive,
I can’t find a command to list all the apps that are in the flatpak usb-drive anywhere.
is it possible to do that ?, if so please let me know.