Leniy

You can easily send subscription,notification,newsletter,etc by email to your comments users under one post. 
方便给某篇文章的评论用户发送订阅、通知等邮件。
DEMO:<a href="http://blog.leniy.org/mail-to-all.html" title="示例页面" rel="nofollow ugc">Leniy</a> 
<a href="https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=HAENMLDR2UMFJ&lc=US&item_name=Leniy%20Plugins%20Donation&item_number=plugin%2ddonate&currency_code=USD&bn=PP%2dDonationsBF%3abtn_donate_SM%2egif%3aNonHosted" rel="nofollow ugc">Donate link</a>

Mail To All

You can easily send subscription,notification,newsletter,etc by email to your comments users under one post.

EmailSystem

<h4>EmailSystem WordPress plugin</h4>
The EmailSystem Sign Up Form plugin makes it easy to grow your newsletter subscriber list from your WordPress website. With this plugin you can generate sign up forms to automatically add subscribers to your EmailSystem subscriber lists.
If you don’t have an EmailSystem account yet, <a href="https://www.emailsystem.app/" rel="nofollow ugc">you can signup for a FREE trial here</a>.
Once you activate the plugin, you may creat sign up forms for new or existing subscriber lists and use it via the provided shortcode.
Setup is fast and easy! You just need to enter your EmailSystem account API token and you’re all set.
All generated forms have double opt-in enabled as well as a mantatory checkbox in order to be GDPR Compliant.
You can also integrate with WooCommerce to place a checkbox for newsletter subscription during checkout.

Use a Drag and Drop Form Builder to create Subscription Forms for the EmailSystem email marketing platform.

Mail To All vs EmailSystem