FastMail

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Gmail

A free an open-source email client developed openly by the Mozilla Foundation and the community. Thunderbird is easy to setup and customize and supports POP and IMAP. The email client comes with all features needed to search, filter, write and manage emails, but also have builtin support for live chat between contact and RSS/Atom feed reader.

World's largest secure email service providing end-to-end encrypted email accounts. ProtonMail is based in Geneva, Switzerland and protected by Swiss privacy laws. The software is openly developed with fully open source code.

K-9 Mail is an open source email client focused on making it easy to chew through large volumes of email. K-9 Mail is designed for both novice and power users and offers lots of features for everyone. It provides features like Push IMAP Support, GPG & PGP/MIME support, Per Account Notifications, Unified Inbox, White and Dark Theme, and Signatures.

World's largest secure email service providing end-to-end encrypted email accounts. ProtonMail is based in Geneva, Switzerland and protected by Swiss privacy laws. The software is openly developed with fully open source code.

HEY is a privacy focused commercial email provider. It brings a fresh approach and transforms email into something you want to use, not something you’re forced to deal with.

Microsoft Outlook is a freemium personal email service and email client created by Microsoft. Microsoft Outlook does not scan your email for the purpose of serving you ads. The Microsoft Outlook email client allow you to be productive and stay connected from your home, on the go, and everywhere in between. Microsoft Outlook also integrates well with other Microsoft service allowing you to reach an eco-system of productive apps from within your mail client, be it in the browser or natively on your computer or mobile device.