Fantastical 2 - Fantastical, the Mac calendar app you'll enjoy using. Quickly create new events with natural language input and more.
Google Contacts - Google Contacts is Google's contact management tool that is available in its free email service Gmail, as a standalone service, and as a part of Google's business-oriented suite of web apps Google Apps.
BusyCal - powerful calendar app for macOS
Google Calendar - Spend less time managing your day & more time enjoying it
Apple Contacts App - Access and edit your contacts from personal, business, and other accounts with the Contacts app.
Superpowered - Power through the day without your calendar