Takuma Morikawa

WP PostNow can encourage posts in the automated email on a regular schedule!
It is possible setting various. 
* Delivery terms of email alerts 
* Check and Mail delivery interval 
* Mail delivery time 
* Select the FuturePosts option(on/off) 
* Send mail user 
* Add Carbon copy mail 
* Mail sender display name 
* Sender address 
* Enter the subject 
* Enter the body
If you are not setting anything, a lower setting is assigned. 
(You can use it right now without any configuration) 
* Mail delivery interval (One week) 
* Check and Mail delivery interval (1day) 
* Mail delivery time (AM10:00) 
* Select the FuturePosts option(on) 
* Send mail user (Administrator) 
* Add Carbon copy mail (None) 
* Mail sender display name (WP-PostNow) 
* Sender address (postnow@yourdomain) 
* Enter the subject (‘your SiteName’ post is stagnated.) 
* Enter the body (‘your SiteName'[ ‘your siteAddress’ ] Let’s post the article right now)
Please note that there is a possibility that can not receive the mail site address and spf record and DNS settings are not set.
<h4>Translators</h4>
<ul>
<li>Japanese(ja) – <a href="http://blog.duffytoy.com" rel="nofollow ugc">Takuma Morikawa</a></li>
</ul>

WP PostNow

WP PostNow can encourage posts in the automated email on a regular schedule.

Scott Kingsley Clark

Requires PHP 5.6+ and WordPress 4.9+
Create and Manage Cronjobs in WP by loading Scripts via URLs, including Scripts, running Functions, and/or running PHP code. This plugin utilizes the wp_cron API.
All you do is install the plugin, schedule your Scripts / Functions / PHP code to run at a specific interval, and live your life — Cron it up!
<h3>Features</h3>
<h4>Administration</h4>
<ul>
<li>Create and Manage Custom Cronjobs</li>
<li>View Custom Cronjob Activity Log</li>
<li>View and Remove Existing Cronjobs</li>
<li>View Available Cronjob Schedules and Intervals</li>
<li>Reset Logs or all Crony settings</li>
<li>Admin.Class.php – A class for plugins to manage data using the WordPress UI appearance</li>
</ul>

Crony Cronjob Manager

Create and Manage Cronjobs in WP by loading Scripts via URLs, including Scripts, running Functions, and/or running PHP code.

WP PostNow vs Crony Cronjob Manager