acsnaterse

Disables all email through wp_mail() on current installation. Email will by disabled by default, but can be overridden in the settings.
<h3>Features</h3>
<ul>
<li>Disables all email by default</li>
<li>Enable email again by matching the given hostname with the current server hostname. </li>
<li>Override the <code>$to</code> address (or multiple, comma sperated addresses), so you can use that for testing purposes.</li>
</ul>
Note: The plugin performs a check on the <code>$_SERVER['HTTP_HOST']</code> variable.

WordPress Disable Email plugin

Disables all email through wp_mail() on current installation. Email will by disabled by default, but can be overridden in the settings.

ffischer

The plugin adds additional BCC recipients to every email that’s sent through 
WordPress’ <code>wp_mail()</code> function. Simply enter multiple comma separated email 
addresses into the BCC Recipient field near the bottom of Settings -> General.

BCC Everything

Blind copy (Bcc) outgoing emails to additional recipients.

WordPress Disable Email plugin vs BCC Everything