Out the Box

Display related posts based on common categories and tags.
Same but Different is a WordPress plugin that adds a list of related posts at the bottom of your blog posts. The related posts are intuitively linked by pulling in any posts that are in the same categories or have the same tags as the post that is currently being viewed. This saves you from the tedious task of manually relating posts.
<h4>Related Posts Widget</h4>
Same but Different also gives you access to a related posts widget. Simply drag and drop the Same but Different widget into your sidebar, enter the number of posts to display and select if they should be linked by categories, tags or both. The widget also allows you to choose whether the related posts should be ordered by date descending or ascending.

Same but Different – Related Posts by Taxonomy

Display related posts based on common categories and tags.

Nitin Kumar Ragahv

[VL Related Posts by Taxonomy] is a powerful plugin for WordPress that allows you to display a list of related posts on your website and in your feed.
It shows the list of posts on the pages on the basis of the vrp-tags. It relates all the posts having the same vrp-tags.
Although several similar plugins exist today, VL Related Posts by Taxonomy is one of the most powerful plugin that can support all of your custom post types. Only you have to select the post types to be suported by this plugin in its options page. It mapped the specified number of posts to the posts only once and stores them in the databse. So that it will not repeat the process of mapping.
<h4>Key features</h4>
<ul>
<li>ShortCode: WRP will start displaying related posts on your site and feed to the place where you will add the ShortCode when you activate the plugin and assign the post types tp display.</li>
<li>Custom Template: You can define your own custom template in the settings page to customize the related posts sections.</li>
<li>Custom Tags: You can define your own custom vrp tags on basis of which related posts section will be populated.</li>
<li>Widgets: Add related posts to widgetized area of your theme. Lots of options available</li>
<li>Shortcode: Use <code>[add_vrp_related_posts]</code> to display the related posts section anywhere you want in the post content
<ul>
<li>Supports for custom description length on specific page by using (<code>description_length</code>) attribute.</li>
</ul>
</li>
</ul>

VL Related Posts by Taxonomy

This plugin is used to add related posts to your WordPress site pages with inbuilt caching. Supports shortcodes and custom post types!

Same but Different – Related Posts by Taxonomy vs VL Related Posts by Taxonomy