Zimbra is the trusted email and collaboration platform and productivity suite that includes contacts, calendar, tasks, chat and file sharing, plus videoconferencing, document editing, and file storage. Built on an open source core, it features a modern interface, pre-integrations with popular third-party apps like Zoom, Slack and Dropbox, and can be deployed in the cloud or in on-prem and hybrid environments. Enterprises, governments, financial institutions, service providers and remote teams around the world rely on Zimbra to support complex privacy, data sovereignty and security requirements. Today, Zimbra powers hundreds of millions of mailboxes on desktop and mobile devices in more than 140 countries, and is offered by more than 500 BSPs and 2,000 channel partners. Also available now for small and medium-sized business is Zimbra Cloud, starting at $2.95 per month for 30 GB of storage. Visit www.zimbra.com to learn more and begin a free trial.
iRedMail - A fully fledged, free email server solution, an open source project (GPL v2).
Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
Roundcube - Web-based IMAP email client
Mailbird - Mailbird is the best email client for Windows 7, 8 and 10
Microsoft Exchange Server - Microsoft Exchange Server is a messaging and collaborative software product developed by Microsoft.
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.