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.

bseddon

On our site we use Easy Digital Downloads. Once an EDD download (e-commerce product) definition has been created it is usually supported by 
other posts that provide additional information – help or tutorial information for example. Ideally, these posts will have a similar style, 
use similar words and need to reference the same core information about the download such a the current version number, the slug, the excerpt, etc..
One way is to cut-and-past information from a download in to each post. But this means that when download details change, its essential to 
remember to update any related posts. This plugin provides another way: a set of plugins that allow you to reference details from a download 
and in this way remove the need to update related posts.
<h4>Features</h4>
Select the linked post using a meta-box dropdown from with in the post definition 
Over 40 shortcode to access post information 
Short-codes to access post field values and to access post meta values 
Access any post meta value by meta key

Download-Post/Page Link

Link posts or pages to an EDD download then use shortcodes in the post to access any field or meta data such as the excerpt, thumbnail and title.

WP Gallery Download Links vs Download-Post/Page Link