Rakesh Raja

This plugin hide content in posts and pages and display only when a user leaves comment. If page/post dont have a comment from user or its got deleated by admin, content will be not displayed.
This plugin uses cookie for that so this plugin will work when user allow website to set cookie.
Restrict it provides you a shortcode [wpgrestrict][/wpgrestrict], wrap your content with this shortcode and you are done.
In next version, I am going to to add restrict content by logged in user. Please let me know if you need any other way to restrict content.
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Restrict It

Restrict content in posts and pages with this plugin and display only when a user leaves comment.

Matthew Muro

Restrict Categories is a plugin that allows you to select which categories users can view, add, and edit in the Posts edit screen.
This plugin allows you to restrict access based on the user role AND username.

Restrict Categories

Restrict the categories that users can view, add, and edit in the admin panel.

Restrict It vs Restrict Categories