Michel Kusters

This plugin adds a download link below every image in your WordPress galleries.
<h3>Gutenberg</h3>
This plugin currently only affects the old-school <a href="https://codex.wordpress.org/Gallery_Shortcode" rel="nofollow ugc">gallery shortcode</a>. The gallery block, introduced with Gutenberg in WordPress 5.0, is not affected.

WP Gallery Download Links

This plugin adds a download link below every image in your WordPress galleries.

This plugin displays all attachments from the WordPress database in the Document Links admin panel, divided into four categories: PDF, Word Docs, ZIP archives and Other. Within the admin panel, you can select which documents you would like to appear, then configure the Document Links Widget and drag it into the sidebar.
You can place as many Document Links Widgets in the sidebar as you like which allows you to show different categories under different titles in the sidebar if you wis,h.
<h3>Requirements</h3>
You must be running WordPress version 2.8 or higher.
You must have a Widget-ready theme installed to use this plugin.
<h3>Instructions</h3>
This is a two-part plugin that requires you to define your settings in both
<ol>
<li>The admin panel</li>
<li>The Document Links widget control panel</li>
</ol>
General description: The Document Links Widget allows you to provide download links to your Media Library files within your sidebar. This can be used for sharing white papers, instructions manuals, presentations or just general file sharing. You must have a Widget-enabled theme installed to use this plugin.
File selection: In the admin panel is a list of all the files in your Media Library. Selecting or deselecting the files here gives you granular control over which files appear within each category. Use the Widget control panel to hide or show the categories.
File names: To change the title of a file, edit the file name in your Media Library.
Order: Display the results by upload date in ascending or descending order.
File link icons: Selecting the show icons checkbox automatically places file icons next to the document links.

Document Links Widget

This plugin allows you to list links to your Media Library files. Great for offering white papers or other document downloads on your website.

WP Gallery Download Links vs Document Links Widget