The most simple way of controlling who sees what in your posts/pages. Restrict content to logged in users only (or guests) with a simple shortcode.
Hide/Unhide Menu for Guest/Member is a simple plugin that you can easily manage to hide or unhide menu for guest and member via css.
Private Files makes sure only logged in users can see images and file attachments.
Allows you to close your site to non-logged in users, by redirecting them to the login page, displaying a message or a specific template file.
This plugin enables a custom theme when the administrator is logged for a safely testing.
File Proxy lest you protect / restrict access to a specific embedded file making sure users are logged in before they can download any files.