We created a cutom “tag” property with multi-select options. BUt there is no way to add an option on the fly. IT requires going to settings/crm/data/properties searching for the propery and editing it. WAy to time-consuming, plus unavailable to those without access to editing properties.
Also in another CRM i use, tags can be organized in outlines which is handy. They aer easy to search on too.