Thunderbird is a free and open source email, newsfeed, chat, and calendaring client application that is easy to set up and customize. There are various third-party plugins available, particularly focused on protecting your privacy and security by offering encryption as an option.

Price: Free

Key Features

• Mail Account Setup Wizard makes it easy for you to set up your email account, simply with your name, email address, and password.
• One-click Address Book is a quick and easy way to add people to your address book by clicking on the star icon in the message you receive.
• Attachment Reminder looks for the word attachment (and other words like file types) in the body of your message and reminds you to add an attachment before hitting send.
• Tabbed Email allows you load emails in separate tabs so you can quickly jump between them and open for easy reference.
• Large Files Management speeds up the transfer of large documents by uploading them to an online storage provider and sharing the link instead of sending the file directly as a message attachment.
• Phishing Protection protects you from email scams and warns you when you click on a link which appears to be taking you to a different Web site than the one indicated by the URL in the message.