A simple and fast cross-platform solution to send mass emails.
The first Open-Source high-performance MTA for high-volume senders
Full SMTP/Mail server Appliance in 5 minutes
A program to send mail via SMTP from command line
Wrappers around msmtp for use as queueing MTA with extra features
Go Gmailer is a java based desktop app to send emails.
Ciphermail email encryption gateway (S/MIME, OpenPGP, PDF encryption)
PHP powerful tool for sending e-mails fast and easily