Will Norris

Comment Saver temporarily stores the content of comments in a browser cookie 
just in case something goes wrong while submitting the comment. For example, 
if the user forgot to include their name and email address and those fields are 
required, the comment may be lost on some browsers. When the user returns to 
the comment form, Comment Saver will automatically populate the comment box if 
the cookie is still set. It will remove the temporary cookie once the comment 
has been successfully submitted, or after one hour.

Comment Saver

Save comment content in a cookie in case something goes wrong while posting.

wpsimpletools

Completely disables comments functionality from backend and frontend: 
* Hides existing comments 
* Close comments on the front-end 
* Disable support for comments, trackbacks and ping 
* Redirects any user trying to access comments page 
* Removes comments metabox from dashboard 
* Removes comments links from admin bar 
* Removes comments page in menu 
* Completely disables comments API

Disable Comments

The type of plugin I just love... does exactly what it says, no configuration necessary, source readable and understandable in minutes.

Simple, effective, no config ✅

Completely disables comments functionality from backend and frontend. Just install it, nothing to configure!

Comment Saver vs Disable Comments