tempranova

This is a simple plugin that uses AJAX to load comments, converting the “Newer/Older Comments” button into a button that loads more comments instantly.
This plugin also paginates nested replies. You can customize styling in whatever way you choose.
Using Settings > Comment Load More, user can set desired pagination (currently both comments and replies have the same number).

Comment Load More

This plugin allows you to load more comments instantly via a button push (AJAX), instead of pagination that reloads the page.

kn007

WordPress Comments Manager help you to quickly find comments and manage comments.
It can be very convenient to review selected comments, open the comment in a new window, reply comment, edit comment and delete comments.
See the screenshots for more details.
<h3>Requirements</h3>
PHP 5.3+, PHP7 recommended for better performance, WordPress 3.6+, WordPress 4.7+ recommended for better experience.

WordPress Comments Manager

Manage your comments faster, handle data more quickly.

Comment Load More vs WordPress Comments Manager