Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...
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.
LightShot - The fastest way to take a customizable screenshot.