The best replacement for combobox is listbox.

The best alternatives to combobox are rated as following:
★★★★★  listbox
★★  dropdown
★★  listbox excel
★★  listbox c#
★★  radio button
★  choicebox javafx
★  dropdownlist
★  filteringselect
★  toolstripcombobox
  listbox access 2007
  listbox vba excel
  listbox vb6
  drop down

Your alternative for combobox is not listed? Suggest!
Speaking about combobox, one probably shouldn't forget about multiple selection.

Other search terms related to combobox and their ratings are:
★★★★★ multiple selection
★ datagrid
treeview
databinding
listview
You have in mind a companion for combobox and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of combobox in all years. Click on graph for more.
combobox
listbox
dropdown