Kontact Alternatives for Mac OS X

Microsoft Outlook is a personal information manager from Microsoft.

Apple Mail is an email client included with the operating systems macOS, iOS and watchOS by Apple Inc.

Postbox is powerful, intuitive, ultra-customizable, speedy task manager.

Calendar is a personal calendar application made by Apple Inc. that runs on both the macOS desktop operating system and iOS mobile operating system.

Rainlendar is a calendar program for Windows, Mac OS X and Linux.

Airmail is a fast mail client for Mac and iPhone.

Sylpheed is an open-source e-mail client and news client licensed under the GPL.

Mutt is a text-based email client for Unix-like systems.

Zimbra Desktop is an offline client that lets you manage various email accounts in one desktop tool.

OpenProject is a web-based project management system for location-independent team collaboration.

Memotoo sync all your contacts from Gmail, Facebook, phone, Thunderbird, Outlook, etc in a single address book.

Contacts is a default contacts management app for Mac based operating systems.

Polymail is an email application for OS X and iOS known for its clean interface and additional features atop the Gmail platform.

MailMate is an IMAP email client for macOS featuring extensive keyboard control, Markdown integrated email composition, advanced search conditions.