Marcin Pietrzak

Display cool, animated fly-out or fade box with related content.
When a reader scrolls to the bottom of a single post, page, or custom post type, an animate box will be shown allowing the reader to select the previous or random available post or posts in the selected configuration:
<ol>
<li>Just previous</li>
<li>Previous in category</li>
<li>Previous in tag</li>
<li>Random</li>
<li>Related using YARPP (only post/pages)</li>
</ol>

upPrev

Great plugin. Works great, lightweight and doesn't take a lot of resources to manage. 

Great Plugin

Display cool, animated fly-out or fade box with related content.

Steve Dufresne

The Beauty Box block provides the ability to surround your content with a configurable container.
The Beauty Box block doesn’t care what you put in the box, it only cares that its beautiful 🙂

Beauty Box Block

Add a customizable box around your content.

upPrev vs Beauty Box Block