Allow manual entries Drop Down list field

Is it possible to also allow manual entry for a Drop Down (single select) field type?

I want to show a limited number of countries but allow people to type in one that is not on the list.

If not, then how do I offer a second, more complete list, if the user has selected Other and then fill in the country field with that?

If not that then how you I enter a long list of countries in the options or the database without having to type them in manually?

Nope, best way to do that is have an Other option then use CB Conditional to show a text field for them to supply their country. Next using the layouts parameters for the country dropdown field substitute in the other field if the dropdown value is other.

As for countries in the database I don't recommend adding them to a normal select field. I suggest having your own database table of countries and using CB Query Field and its Query Select type to build the dropdown options from that table.