xmailheaders is a mail notification utility that is based on the "mailbox" utility that's avilable on Solaris workstations. The idea is that it sits on your desktop somewhere, periodically polling the mail server/spool for new messages. New message headers are displayed as they come in. Supported mailbox formats are POP3, IMAPv4, and Unix mbox. SSL-based password authentication is also supported for POP and IMAP.
xstress is a small yet powerful tool to stress test SMTP mail servers. xstress creates multiple threads and sends mail messages with varying subjects, "to" addresses, and body texts. Mail attachments are supported. All the parameters are highly configurable. For example, you can configure the number of threads xstress creates, SMTP timeout, attachment files, "to" address, "from" address, etc.
ytnef_cg_filter.pl provides a content filter program for the Stalker CommuniGate Pro email server that performs extraction of TNEF (winmail.dat) attachments by utilizing ytnef. It also has the ability to scan attachments with Clam Antivirus, as well as block them based on regular expressions. Its goal is to ease interoperability between mixed Windows and Linux workgroup environments.
zmaildrop is a mail delivery agent (MDA) specifically designed to analyze emails, extract relevant information, and send it to a Zabbix server. It is designed for use with schedulers, backup tools, and security monitoring tools that report information via email. As an MDA, it integrates easily with mail transfer agents (MTA) such as Postfix, Exim, and Qmail, or mail retrieving tools as Fetchmail. It is highly configurable, using a simple YAML syntax to describe tool-specific mail formats.