Here is small video on MQTT using Flutter and riverpod.
Often when we develop apps where we need to populate list of countries, search them etc, you may go by adding the data statically or using apis, but here lets use the power that lies with in your mobile phones. Most of the mobile system OS has these information embedded and we can avail those. I encountered a requirement while I was doing a personal project. I managed to create a plugin so that it benifit others, here you go https://pub.dev/packages/iso_countries