Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!

Sun Surveyor - Sun Surveyor calculates Sun and Moon Positions, Sunrise & Sunset and Moonrise & Moonset...

Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.

Natural Hour - A roman timekeeping add-on for Suntimes.

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.

Sol: Sun Clock - Get reminded when it's sunrise or sunset, wherever you travel!