Hinaloe

This plugin allow your site’s comment form makes ajax — non move/reload when user (including both subscriber, normal viewer, and admins too) post comment!
Most themes supports this plugin, but if your theme’s <code>class_form</code> have not <code>comment-form</code>, this plugin non supported.
And this plugin only can use for Pure WordPress Comment form. 
so, its not able to be used with like Jetpack comment form and other original/outside comment system/form.
Feature
<ul>
<li>post comment with ajax</li>
<li>Lite — this plugin only using a little of jQuery feature to modify DOM, and very tiny js & PHP code.</li>
</ul>
Require
You have to install <a href="https://wordpress.org/plugins/rest-api/" rel="ugc">WP REST API v2</a> to use this plugin if your site is running on WP 4.4-4.6.

ajax Post Comment

Post comment form on frontend tobe ajax using WP REST API Version.2

Josh Pollock

Any post type that works with the WordPress REST API (show_in_rest must be true when declaring post type) will be queryable with /wp/v2/posts
Example Queries
<ul>
<li>GET wp/v2/posts?type=roy</li>
<li>
GET wp/v2/posts?type[]=roy&type[]=mike
A free plugin by <a href="http://calderalabs.org?utm_source=dotOrg&utm_medium=plugins&utm_campaign=rest-api-multiple-post-types" rel="nofollow ugc">Caldera Labs</a> the makers of <a href="https://calderaforms.com?utm_source=dotOrg&utm_medium=plugins&utm_campaign=rest-api-multiple-post-types" rel="nofollow ugc">Caldera Forms</a> a drag and drop responsive form builder.
</li>
</ul>

REST API Multiple Post Types

Query multiple post types using /wp/v2/posts

ajax Post Comment vs REST API Multiple Post Types