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.

Kushang Tailor

Now manage your Media files security with this plugin. This plugin is provide allow and disallow different upload file Mime types to the WordPress Media Library. In other words, Restrict the Mime types or extensions as per your wish.
Almost 96 extensions and Mime types are available.

Restrict WP Upload Type

This plugin is use for to allow and disallow different upload file Mime types to the Wordpress Media Library. Easy to use and flexible.

Restrict It vs Restrict WP Upload Type