Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Clocker - Keep track of people in different time zones
Mailbird - Mailbird is the best email client for Windows 7, 8 and 10
Dato - Better menu bar clock with calendar and time zones
eM Client - eM Client is a fully-featured email client for Windows and macOS with a clean and easy-to-use interface. eM Client also offers features for calendars, tasks, contacts, notes, and chat.
Clock mini - Simple clock app in the Dock