WordPress.org

Ella

This plugin allows you to create documents with WordPress, and to share them with others so they can also read and edit. Share the unique link to let anyone edit, or restrict access to specific email addresses.
With the Gutenberg plugin, Docs supports real-time collaborative editing — multiple users can edit the same document simultaneously, seeing each other’s cursors and changes live.
<h3>Sharing</h3>
The share panel (in the document sidebar) lets you control access:
<ul>
<li>Anyone with the link — anonymous users get a randomly generated animal name and emoji avatar (e.g. “Anonymous Fox”). They can edit text but cannot upload files.</li>
<li>Specific people — invite collaborators by email. They receive a magic link to access the editor. Email-invited users can upload files.</li>
<li>Existing users — add collaborators from the user autocomplete. They get full editing and upload access.</li>
<li>Restricted — only the document author and invited people can access.</li>
</ul>
<h3>How it works</h3>
Documents live entirely in wp-admin — there’s no public frontend. Each doc gets a unique and secret shareable URL that opens the editor directly.
Anonymous visitors don’t create any database entries. Their identity exists only in a browser cookie and disappears when it expires.
Email-invited people are created as real WordPress users (without a role) so their edits show up in revision history. They log in via magic links sent to their email.

Docs

how it works? 
Can I use it in the classic editor?

how it works

Create and share documents with WordPress!

sstukov

<a href="http://userlook.com" rel="nofollow ugc">UserLook</a> – real time analytics of your blog activity.
UserLook WordPress plugin – allow easy to integrate UserLook tracking code to your blog.
Be aware of what is happening in your blog, find out about it first.
Live dashboard – updates instantly with every action that occurs on your website. You get a quick overview of exactly what’s happening without refreshing.
Please note, this plugin requires a account on <a href="http://userlook.com" rel="nofollow ugc">UserLook</a> 
UserLook service cost, starting from 4.95 monthly, we have free 15 days evaluation period.
<a href="http://feedback.userlook.com/topic/78009-add-wordpress-plugin/" rel="nofollow ugc">Plugin support community</a>

UserLook

Integrate UserLook - real time analytics of your blog activity. Live dashboard.

Docs vs UserLook