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.

Brandon Himpfen

Disable WP Emojis allows you to remove emojis from your WordPress site’s front-end, including 
the feeds, as well as the administration panel pages and e-mails.

Disable WP Emojis

Removes emojis from the WordPress front-end, admin pages, feeds and e-mails.

Manly No Emojis vs Disable WP Emojis