Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Litmus - litmus tests and tracks your email campaigns, so you can always put your best design forward.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Brevo - Innovative online Email Marketing solution to manage your contacts, create & send your newsletters and track your results. More than 80 000 clients. Best prices and attractive features.
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.
250ok - 250ok offers a SaaS-based platform to monitor and measure the deliverability of email networks.