Tranons

A simplistic plugin that allows for the furthur customization of your category list. This will allow you to create a custom category list which will show the categories you want, and will hide the categories you do not want. For example, say you have a particular category you don’t want to be displayed named “Announcements”. You can use this plugin to display all of your other categories, except the category “Announcements”. You are not limited to just excluding one category; you can exclude multiple categories. Essentially, this plugin provides more functionality to your category list.

Category Excluder Widget

This widget allows you to easily create a specific category list. You can exclude any categories you please.

Andy Feliciotti

This plugin adds a “Unlisted?” checkbox in the “Publish” box while using the classic editor and Gutenberg. When this is checked the post will be excluded from most areas of your website by filtering pre_get_posts filter. This means posts will be excluded from RSS feeds, blog pages, widgets, category pages, archive pages, and more. Additionally it adds a noindex tag to the unlisted page to prevent Google from indexing the page. This is useful if you want to publish some information on your site and allows others to view it via the link without fully publishing.
Features
<ul>
<li>Simple checkbox to unlist posts when publishing a post</li>
<li>Allows you to hide posts from most areas of your site</li>
<li>Add a noindex tag to pages that are unlisted</li>
</ul>

Unlisted Posts

Allows you to easily exclude posts from feeds, category pages, blog pages and more using one checkbox on posts.

Category Excluder Widget vs Unlisted Posts