Postfix - Postfix is a mail transfer agent (MTA) that routes and delivers electronic mail.
Microsoft 365 - Boost your productivity with reliable access anywhere with services like email, calendar, file sharing, meetings, instant messaging, and Office Online
mailcow - An open source mailserver suite.
Apache OpenOffice - Apache OpenOffice is an open source, office document productivity suite.
Mail-in-a-box - Mail-in-a-Box provides webmail and an IMAP/SMTP server for use with mobile devices and desktop mail software and also includes contacts and calendar synchronization.
SoftMaker Office - SoftMaker Office is one of the most powerful and reliable office suite that is fully compatible with the MS Office Suite.