kappuccino

This plugin allow WordPress to generate animated thumbnail from GIF files, instead of static files.
This plugin uses image magick <code>convert</code> to generate smaller gif, your server needs to have it. A check 
is done during activation, so if you do not have acces to <code>convert</code> this plugin will do nothing.

WP Gif Resizer

This plugin allow WordPress to generate animated thumbnail from GIF files, instead of static files.

Pete Nelson

Animated GIFs are large. The GIFV format introduced by <a href="https://blog.imgur.com/2014/10/09/introducing-gifv/" rel="nofollow ugc">Imgur</a> 
solves this problem by converting animated GIFs to MP4 and embedding them in an HTML page. This plugin 
leverages the <a href="https://api.imgur.com/" rel="nofollow ugc">Imgur API</a> to convert animated GIFs hosted on your WordPress site 
into locally hosted GIFV URLs.
<ul>
<li>Adds “Convert to GIFV” to the Media Library</li>
<li>Creates URLs for converted GIFV files (ex: mysite.com/animated.gifv)</li>
<li>Twitter card and Facebook opengraph support for sharing</li>
<li>WP-CLI support via “gifv” </li>
</ul>
Plugin name inspired by <a href="https://wordpress.org/plugins/son-of-clippy/" rel="ugc">Son of Clippy</a>
Find us on <a href="https://github.com/petenelson/son-of-gifv" rel="nofollow ugc">GitHub</a>

WP Gif Resizer vs Son of GIFV