DimitriAus

This lightweight plugin removes WordPress emoji functionality to reduce HTTP requests and improve page load times.
What it removes:
<ul>
<li>Emoji detection script from page head</li>
<li>Emoji styles from frontend and admin</li>
<li>TinyMCE wpemoji plugin</li>
<li>Emoji conversion in RSS feeds</li>
<li>Emoji handling in emails</li>
<li>DNS prefetch for emoji CDN</li>
</ul>

Manly No Emojis

Disables the emoji functionality in WordPress to improve performance.

WPDO

Add the slack style emoji to posts, pages or comments.
<h4>Features:</h4>
<ul>
<li>
React with emojis to any post or comment.
</li>
<li>
Post View counter. Compatible with all cache plugins! Easy to use. Automatically exclude bots.
</li>
<li>
Disable comment on any post type (pages, posts, attachments).
</li>
<li>
Most Viewed widget. Recent Reacted Emoji Post widget.
</li>
<li>
Allow guests reaction or logged-in user reaction only.
</li>
<li>
GDPR compliant. With this feature turned on, all logged IPs get obfuscated (md5-hashed).
</li>
</ul>
<h4>Post View</h4>
<ol>
<li>
Edit <code>wp-content/themes/<YOUR THEME>/index.php</code> or <code>archive.php</code>/<code>single.php</code>/<code>post.php</code>/<code>page.php</code>.
</li>
<li>
In the loop <code>while ( have_posts() ) {</code> or anywhere you want to show the views, add the following codes: <code>do_action( 'remoji_postview' );</code>.
</li>
</ol>
API
To show postview in themes/plugins, use <code>do_action( 'remoji_postview', $the_post_id_to_inquire );</code>.
Shortcode [views] available
Use <code>[views]</code> or <code>[views id="3"]</code>(To show the views of post ID 3) in your editor.

Remoji – Post/Comment Reaction and Enhancement

I like this because it allows one to react in many different ways in posts and comments. And it looks nice and doesn't take up a lot of space. One issue though is if you turn on IP privacy, someone is able to react repeatedly. If improvements are considered, then I suggest the following:

1) Add an option to track by logged in user, and also that would mean only people logged in can use it.
2) That would solve the reacting over and over again but for those would want to allow visitors to react then there would have to be another way to prevent excessive reacting. Or, at least a warning that if you turn on IP obfuscation then people will be able to react over and over. 
3) I hope you can one day add the ability to delete reactions.
4) A widget showing most reacted posts would be cool too.

Very nice

Reactive emoji. Allow visitors to add emoji reactions to your posts and comments. Disable comment for pages, posts.

Manly No Emojis vs Remoji – Post/Comment Reaction and Enhancement