I would love a selection list that allowed for a hierarchical menu.
Continent->Country->City

There is Selectize, but that does not really meet my needs. I do not need it to cover the whole world. For FPGA related things most of the work is done in a small number of locations around the world. Some countries I want to cover in more detail, other countires, I am happy not even listing the cities.

I suspect that I can add this myself, but maybe I will get lucky and it already exists.