Zimbra Desktop is an offline client that lets you manage various email accounts in one desktop tool. Developed by Zimbra
License: Free Personal
Zimbra Desktop is a versatile, open-source email client that supports multiple platforms and email protocols, making it suitable for various users. In contrast, MailMate is a macOS-exclusive app that offers a modern interface and powerful features like Markdown support and advanced search, catering specifically to macOS users.