It's an interesting question. Some of them are definitely from the OS (either Google or Samsung).

Looking through at categories of app where I have multiple, I'm seeing:

- Transport provider apps (Airlines, Trains, Buses, Taxis etc)

- Parking payment apps

- Food delivery apps

- Hotel apps

- Payment apps

- Messaging / Video calling apps

- Banking apps

- Mapping apps

It's especially easy to accumulate a lot of apps if you travel through multiple countries, as for a lot of these apps you need different ones in different countries.