Microsoft 365 - Boost your productivity with reliable access anywhere with services like email, calendar, file sharing, meetings, instant messaging, and Office Online
Postfix - Postfix is a mail transfer agent (MTA) that routes and delivers electronic mail.
Apache OpenOffice - Apache OpenOffice is an open source, office document productivity suite.
mailcow - An open source mailserver suite.
SoftMaker Office - SoftMaker Office is one of the most powerful and reliable office suite that is fully compatible with the MS Office Suite.
MailerQ - MailerQ is a high performance Mail Transfer Agent (MTA) designed for delivering large volume email messages at very high speeds.