hMail Server - hMailServer is a free e-mail server for Microsoft Windows.
AODocs - AODocs is the document management solution recommended for G Suite. Secure your documents, structure your content, & automate your processes
Postfix - Postfix is a mail transfer agent (MTA) that routes and delivers electronic mail.
Docomotion - Docomotion offers tools for designing and generating all types of transactional and operational business documents.
PowerMTA - PowerMTA is an industrial-strength software for high-volume email delivery.
infoRouter - infoRouter is a EDMS that includes Workflow, Document routing, Electronic Forms, Scanning, Storage, Archiving, Indexing & Records Management