mores

For some reason or other, you might want to allow access to certain posts only to certain people. You can use password-protection on Pages and Posts, but those need to be set individually. 
It’s far simpler to just write a Post, specify a category and all posts in that category are password protected. Or you might decide to protect a lot of old posts. 
Imagine a family blog where certain posts are only visible to people who know the birthday of your first child, or remember your pet’s name. 
Cat-Pass is not for super-sensitive information, it’s for casual use.

Cat-Pass

Cat-Pass lets you password-protect categories. Caution: deactivating the plugin will render your protected posts visible again.

Dozty

A basic security plugin for WordPress 4.x, 5.0 or higher. You can selectively disable unused features in WordPress core, and this plugin will help you to remove unnecessary information to be disclosed to attackers. You can find more details in the User Manual.
Basic WP Security Hardening: 
– Remove WP Version Details 
– Disable XMLRPC 
– Disable Pingback 
– Disable Windows Live Writer 
– Disable RSS Feeds 
– Disable JSON & REST API 
– Enable Security Headers (X-Frame-Options, X-XSS-Protection, X-Content-Type-Options) 
– Remove PHP Version Header
Optional Settings: 
– Remove HTML Comment Tags 
– Trim HTML Response
Custom Login URL: 
– Customize Login URL 
– Customize Login Logo URL 
– Enforce HTTPS Login

DozWPSecure

A basic security plugin for WordPress 4.x, 5.0 or higher. You can selectively disable unused features in WordPress core...

Cat-Pass vs DozWPSecure