24me - Next Generation Personal Assistant
Google Calendar - Spend less time managing your day & more time enjoying it
WeekCalendar - WeekCalendar is an all-in-one calendar application designed to provide everyone with all the features they need to work to their fullest.
BusyCal - powerful calendar app for macOS
Pocket Informant - Pocket Informant is the Best Calendar app for mac and iOS. Pocket Informant for iOS, Mac desktop, and Android.
SmartDay - Integrated organizer with automatic scheduling.