Value Type Saved (Dropdown): IEnumerable<string>
Value Type Saved (Radio): String
Value Type Saved (Checkbox): IEnumerable<string>
These list content properties are very customisable. You can either add in manual data or use data from any data source (Database, file etc...) using the IDataListSource.
When you add a list content property, click the settings icon to configure the property
Showing the editors in the content editor (All pickers are using the content views IDataListSource)