mailcow - An open source mailserver suite.
Conga Contracts - Conga Contracts is management solution designed to accelerate and simplify contract negotiations in Salesforce.
hMail Server - hMailServer is a free e-mail server for Microsoft Windows.
ContractWorks - ContractWorks provides secure and easy-to-use contract management software that helps you gain control of your contracts.
SmarterMail - SmarterMail is a next generation email management server that is offering several business collaboration and communication features as well.
Concord - Contract Management Software and unlimited Electronic Signatures. Reduce costs, maximize compliance & mitigate risk. Enterprise solutions available.