The Random Featured Post plugin allows you to display a random post from a designated category. Ideally this should 
draw readers landing on your homepage to some of your best posts. The featured post will display the title 
“Featured Post” (customizable) along with the post’s title, an excerpt and a link to continue to the full post.
<h3>Additional Notes</h3>
<ul>
<li>The show_featured_post($PreFeature = ”, $PostFeature = ”, $AlwaysShow = false, $categoryID = 0, $NumberOfPosts = 0) function has five optional arguments. 
The first two are for any HTML you would like to display before and after the featured post. The third argument is a 
boolean (true/false) argument which will override the \’Show Featured Post\’ option and always display the featured post when true. The fourth option allows you to 
specify a single category to display from, overriding the selections in settings page. The fifth option allows you to show more than one post at a time, overriding 
the settings page option.</li>
<li>All output is contained in a DIV class named “featuredpost” and can be adjusted via your stylesheet.</li>
</ul>

Random Featured Post

The Random Featured Post plugin allows you to display a random post from a designated category as a "featured" post.

binarymoon

jwall

Front Page Category is a plugin that let you select the categories that appear on the front page of your website. If there are categories that you don’t want to appear on front page, for example the ‘uncategorized’ one, just go to the Customizer → Front Page Categories menu, and then untick the categories you want to hide.
This could be useful if you use an automated posting system, or use email to post. In these cases you can assign these posts to a category of your choice and uncheck it at Front Page Category settings. They will then be hidden from the homepage – but will still appear on their category page.

Front Page Category

I use his for hide category, a kind of second parallel blog.

Good Plugin for 2nd blog:)

A plugin that lets you select the categories that appear on the front page of your WordPress site.

Random Featured Post vs Front Page Category