https://formidableforms.com/knowledgebase/frm_setup_new_fields_vars/

and

https://formidableforms.com/knowledgebase/frm_setup_edit_fields_vars/

This is from my current project, a directory of editors, proofreaders etc. You provide the Get*Options functions, which return arrays of items of the form Name|Id or whatever terms you use. The 'categories' above appear in the dialog when you click 'Bulk Edit Entries' for a list control. Clear the present list (if there is one) and click the approriate item. Do this every time you edit the underlying data or changes won't be seen in the lists in the forms.Maybe there's a way to completely automate propagating data changes to the lists. My data doesn't change often enough for me to bother investigating that.