Marco Milesi

WP Attachments enhances the download experience and file management in WordPress. It automatically displays attachments in your posts and pages, so you don’t need to manually insert download links. 
Easily attach, unattach, or reattach files directly from the media library.
Key Features: 
– 🤖 Automatically displays attachments after post content 
– ℹ️ Backend metabox for managing attachments 
– 🔃 Quick Attach, Unattach, and Reattach actions in the Media Library 
– 🔢 Download counter with anti-spam and logged-in user filtering 
– 🧑‍💻 Developer hooks and filters for customization 
– 🛍️ WooCommerce compatible 
– 🎨 Five icon packs to choose from 
– 📜 Supports posts, pages, and custom post types 
– 🎢 Customizable themes (title, date, size, caption, and more)
<a href="https://www.youtube.com/watch?v=J7gf0hxl_z8" rel="nofollow ugc">Video Overview</a>
<h3>Contributions</h3>
<ul>
<li>Part of <a href="http://www.wpgov.it" rel="nofollow ugc">WPGov.it</a>, providing open source solutions for Italian Public Government websites.</li>
<li>Thanks to the Italian community <a href="http://www.porteapertesulweb.it" rel="nofollow ugc">Porte Aperte sul Web</a> for beta testing and ideas.</li>
<li>Metabox based on <a href="https://wordpress.org/plugins/ij-post-attachments/" rel="ugc">IJ Post Attachments</a></li>
<li>Some icons by <a href="http://p.yusukekamiyamane.com/" rel="nofollow ugc">Yusuke Kamiyamane</a>.</li>
</ul>

WP Attachments

Nice and useful plugin. The only downside is that it lacks a setting to show image thumbnails instead of a generic image icon in the edit metabox.

Show thumbnails instead of icons in metabox

A powerful solution to manage and display your WordPress media attachments in posts and pages.

This plugin will allow you to attach a single file to multiple posts, but will also will allow you to detach any file.
<ul>
<li>Support http://xparkmedia.com/plugins/file-un-attach/</li>
<li>Languages http://xparkmedia.com/plugins/file-un-attach/#languages</li>
</ul>

File Un-Attach

This plugin will allow you to attach a single file to multiple posts, but will also will allow you to detach any file.

WP Attachments vs File Un-Attach