Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
XML Copy Editor - XML Copy Editor is a fast, free, validating XML editor.
Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Oxygen XML Editor - Oxygen XML Editor provides a comprehensive suite of XML authoring and development tools.
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.
Liquid Studio - XML Tools Provider: XML Studio - Graphical XML Schema Editor.