FolioVision

This plugin reconfigures the wp_mail() function to use SMTP instead of mail() and creates an options page that allows you to specify various options.
You can set the following options:
<ul>
<li>Specify the from name and email address for outgoing email.</li>
<li>Choose to send mail by SMTP or PHP’s mail() function.</li>
<li>Specify an SMTP host (defaults to localhost).</li>
<li>Specify an SMTP port (defaults to 25).</li>
<li>Choose SSL / TLS encryption (not the same as STARTTLS).</li>
<li>Choose to use SMTP authentication or not (defaults to not).</li>
<li>Specify an SMTP username and password.</li>
</ul>
Also adds subject to headers for SendGrid Activity Screen. SengGrid is a powerful SMTP service, however it’s Activity Log screen misses the message subjects. Our plugin adds that back in!

WP Mail SMTP SendGrid Edition

Based on WP Mail SMTP. Also adds subject for display on SendGrid Activity Screen.

EverPress

Xaver

Mailster Newsletter Plugin

A Dummy Mailer for the <a href="https://mailster.co/?utm_campaign=wporg&utm_source=wordpress.org&utm_medium=readme&utm_term=Dummy+Mailer" rel="nofollow ugc">Mailster Newsletter Plugin for WordPress</a>. Requires at least version 3 of the Mailster Plugin
<blockquote>
This Plugin requires <a href="https://mailster.co/?utm_campaign=wporg&utm_source=wordpress.org&utm_medium=readme&utm_term=Dummy+Mailer" rel="nofollow ugc">Mailster Newsletter Plugin for WordPress</a>
</blockquote>
<h3>Additional Info</h3>
This Plugin requires <a href="https://mailster.co/?utm_campaign=wporg&utm_source=wordpress.org&utm_medium=readme&utm_term=Dummy+Mailer" rel="nofollow ugc">Mailster</a>.
Please note the DummyMailer may require a lot of memory so having at least 256MB of RAM enabled is recommended!

Mailster DummyMailer

A Dummy Mailer for the Mailster Newsletter Plugin for WordPress. Requires at least version 3 of the Mailster Plugin

WP Mail SMTP SendGrid Edition vs Mailster DummyMailer