Postfix - Postfix is a mail transfer agent (MTA) that routes and delivers electronic mail.
Airtable - Airtable works like a spreadsheet but gives you the power of a database to organize anything. Sign up for free.
sSMTP - sSMTP is a simple MTA to deliver mail from a computer to a mail server.
Creativity 365 - Cross-device content creation suite
Sendmail - Sendmail is a general purpose internetwork email routing facility that supports many kinds of...
Microsoft Teams - Microsoft Teams provides the enterprise-level security, compliance and management features you expect from Office 365, including broad support for compliance standards, and eDiscovery and legal hold for channels, chats, and files.