Google Calendar - Spend less time managing your day & more time enjoying it
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.
Simple Calendar - A simple calendar with events (optional recurring and reminders), week numbers and a customizable...
Nextcloud Contacts - The Nextcloud contacts app is a user interface for Nextcloud's CardDAV server.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Microsoft People - People in Windows 10 puts all the ways you connect with all your friends, family, colleagues, and acquaintances in one place, so it’s faster than ever to keep in touch.