Teamup Calendar - Cloud-based calendaring using capability URL, application developed in Zurich, Switzerland.
Fantastical 2 - Fantastical, the Mac calendar app you'll enjoy using. Quickly create new events with natural language input and more.
Google Calendar - Spend less time managing your day & more time enjoying it
BusyCal - powerful calendar app for macOS
Kin Calendar - The simple and connected calendar
OfficeCalendar - Share Microsoft Outlook calendar and contact folders