it will be great if you add SfCountryPicker to display the countries in SfPicker. I know it is possible to do it programmatically but the Date and Time is also possible and Syncfusion added a great SfDatePicker and SfTimePicker which saved a lot of time for the developers.
The SfCountryPicker should have the following:
Country Name English
Country Name [Other Languages]
Country 2 Characters ISO code
Country Flag Images
it should be able to retrieve the country name (in selected languages) and country code.
There is also be an option to hide one or more countries.