This plugin provides facilities for monitoring the system mail queue

The_path lets you write email chains and classes in a convenient DSL. After building a simple DSL structure for a series of emails, they can be loaded into a mailing service such as MailChimp for use with real humans.

A microframework for mail-centric applications

This Rails gem allows you to send X509 signed and\or crypted mails.

plugin to send mail notifications for build release

Exports address books from various e-mail services (Gmail, Mail.ru, Yandex, Rambler)

Use AppMail with the Ruby mail gem

A utility to send commit mails for commits pushed to git repositories.

A mail utility so dense, no message can escape.

MailGrabber is yet another solution to inspect sent emails.

trace mail relayed in intra network.

LesliMailer provides a flexible and extendable mailing system designed for applications built on top of The Lesli Framework.

ArMailer wrapper for Rails 3 with mail priority

IOMailer is a simple script for executing commands and shell scripts, collecting their output and mailing it to designated email addresses.

Ruby gem to interact with the Maileroo API.

Lita handler for interacting with mailgun.com

MailBuilder is a simple library for building RFC compliant MIME emails.

Determine configuration details for a mailbox using Mozilla's ISPDB

Simple client wrapper for Mailgun API using Faraday client

Tool for sending fast mailings in one SMTP connection