WPKube

The plugin restores the <code>Title</code> field (that was removed from WordPress 4.2) in the insert link popup box and adds a new <code>Add rel="nofollow" to link</code> checkbox to it.
Gutengerg (Block Editor) Note: At the moment it’s not possible to add the functionality to Gutenberg, it’s a different system from the classic editor and it does not have a hook/filter which allows adding custom settings. As soon as it becomes possible to add the functionality to Gutenberg we will update the plugin.
This plugin has been adopted and maintained by <a href="https://www.wpkube.com/" rel="nofollow ugc">WPKube</a>, a popular WordPress resource site, where you can find guides on <a href="https://www.wpkube.com/category/wordpress-plugins/" rel="nofollow ugc">WordPress plugins</a>, <a href="https://www.wpkube.com/best-wordpress-hosting/" rel="nofollow ugc">WordPress Hosting</a>, and more.

Title and Nofollow For Links (Classic Editor)

I just installed this on WP 4.9, and it works like a charm. I ended up adding HTML Class manipulation as well, by coping the code in the JS file that added the title field.

Works Well

works with wp 5.2.1

Helpful tool

The plugin adds a title and a rel="nofollow" checkbox to the insert link popup box. Only for Classic Editor, NOT Block Editor.

Fabio Santos

This plugin adds a simple checkbox in the insert/edit link popup for including nofollow attribute.

Rel Nofollow Checkbox

Adds a checkbox in the insert/edit link popup for including rel="nofollow".

Title and Nofollow For Links (Classic Editor) vs Rel Nofollow Checkbox