Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
ScreenTray - A better way to capture, annotate and share screenshots
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Annotate by Convergely - Easily annotate images you get on Slack - just like Skitch
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.
Weava - Workspace to highlight, organize & collaborate on your research articles.