theode

With the use of shortcodes it is possible to react to the content by emojis. 
So you install the plugin and create new emoji with a title an emoji itself, a count field and an initial count, to fake the initial value of the clicked emoji. 
The shortcake is [emojized id=“8” count=“true”] (or false or empty)
In the new version you can limit votes to one per user.
This plugin demands WP REST API plugin.
It has the same approach as the plugin “Emoji Reactions” 
https://wordpress.org/plugins/emoji-reactions/ 
but that seems to be discontinued.
https://www.youtube.com/watch?v=VaNw_Xh35NM
So have fun with emojis.

Emojized

Emojized allows visitors to a WordPress site to rate and react to content using Emojis. Because text without them is  🅱🅾®ℹ️🆖

stuartquin

Emoji Reactions allows visitors to a WordPress site to rate and react to 
content using Emojis.
<ul>
<li>Full set of emoji from <a href="http://emojione.com" rel="nofollow ugc">EmojiOne</a></li>
<li>Support for range of content – posts, pages, comments.</li>
<li>Track user votes – only one of each reaction per user per content item.</li>
<li>Shortcode support – add reactions anywhere in content</li>
</ul>

Emoji Reactions

Add emoji reactions to posts, pages and comments. Inspired by Slack

Emojized vs Emoji Reactions