Duct connectors in Revit Families only include Supply, Return, and Exhaust air. There should be options for either "Makeup-Air" or "Outside-Air" as a System Classification for ducts.
HVAC systems and equipment often pull air from the outside of a building, and this type of air system is shouldn't be stuck using "other"; having a specific System Classification for Outside Air would help clarify the connections' intended use for end-users.