Here is the list of very useful plugins that helps the wordpress plugins & theme developers. This plugins helped our team to easily debug and test code which will reduce development time.

WP Mail Logging is a plugin to log emails sent by WordPress or WooCommerce. By default, WordPress and your web host do not log, store or keep track of emails sent from your website. WP Mail Logging help you to know which emails your WordPress sends for debugging purposes. Simply activate it and it will work immediately, no configuration necessary.

WordPress.org Plugin Page : https://wordpress.org/plugins/wp-mail-logging/

Simply Show Hooks helps theme or plugin developers to quickly see where all the action and filter hooks are on any WordPress page.

WordPress.org Plugin Page : https://wordpress.org/plugins/simply-show-hooks/

Preview E-mails for WooCommerce is a plugin for WooCommerce that lets you Preview Emails, without having to send them.

WordPress.org Plugin Page : https://wordpress.org/plugins/woo-preview-emails/

Suggestion & Feedback: If you have any addition, deletion or correction to the list, then write it on below comment. Our team will review and update the list.