uamv

Common Links allows you to add regularly used links to the search results when linking text content of your post.
Add your common links from the Tools menu. Then, when linking content, begin typing the link title or URL to pull up and insert the link.
Note: Entering <code>.</code> when querying links will not return results. Use spaces instead to match URLs.

Common Links

Adds custom links to the editor's link query

jmarreros

This Plugin allows to use an external image as Featured Image, this can be especially useful if you house your images in another location.
This Plugin is compatible with Nelio External Featured Image Metadata, so you can reuse your data in case you want to uninstall Nelio Plugin.

External URL Featured Image

It is what I was looking for: simplicity.

$external_image = get_post_meta( $post->ID, '_dcms_eufi_img', true );

Works well for me

Use an external url image as Featured Image for your posts, pages, and other kind of post types.

Common Links vs External URL Featured Image