Ashish Kumar (Ashfame)

Prevents WordPress from sending out emails and save them so that you can preview them without actually having to send them. Best for checking or designing emails in development environment.
Please report any issues directly to Github repo – https://github.com/ashfame/email-cop/
Pull requests are welcome 🙂
Icon Credit: Cop icon – http://www.aha-soft.com/

Email Cop

I use this for all my local installs. It's so helpful and necessary. We recommend it to all our GiveWP users so they can test their emails on staging or locally without worrying that they'll end up blasting their donors. 

So great and easy and does its job well. Thanks!

So helpful and necessary

Prevents WordPress from sending out emails and save them so that you can preview them without actually having to send them.

Automattic

Daniel Bachhuber

A quick and easy way to see post meta associated with any given post. When activated, this plugin prints your post meta keys and values inside of a post meta box.
Originally developed for <a href="http://vip.wordpress.com/" rel="nofollow ugc">WordPress.com VIP</a>-hosted clients, we thought it would be useful for development environments, etc. too. Feel free to <a href="https://github.com/Automattic/Post-Meta-Inspector" rel="nofollow ugc">fork the plugin in Github</a> and pull requests are always welcome. Hit us with feedback, questions, bug reports, and feature requests in the forums.

Post Meta Inspector

Lovely little tool. Saves having to go into the database and look through the postmeta table when debugging. Thanks!

Email Cop vs Post Meta Inspector