Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
144blocks - Colorful way to track your time! Inspired by Wait But Why
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Clock mini - Simple clock app in the Dock
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.
World Clock iOS 8 Widget - Check the time, anytime. Just pull down Notification Center.