Abidemi Kusimo

You can make use of category popular tag to display most used tag on your blog. This will give list of frequently used tag anywhere you place the shortcode or funtion in your theme.
For example [popular_category_tags count=10 type=”popular-tags” category_id=”1″]. 
You can also call this function from your theme file: cush_category_popular_tag() for basic output.
When using the shortcode type is required. category id, count is not required. if no category id suplied, the plugin will default to current post category available. 
For example [popular_category_tags type=”popular-tags” ].
You can find category tags options under Settings page 
Settings -> Category Tags
Credit : (https://wordpress.stackexchange.com/questions/261617/display-most-popular-tags-of-category)

Category Popular Tags

Display popular tags on achieve/category page of your theme using sortcode or by calling a function.

This is a simple popular posts WordPress widget for your blog. Add and day interval to specify when the posts are considered popular, the default is 365 (one year) you can also filter your post by category. Enjoy!! and please support the plugin. :@)
<ul>
<li>Languages http://xparkmedia.com/plugins/popular-widget/#languages</li>
<li>Support http://xparkmedia.com/support/plugin/popular-widget/</li>
</ul>
<h4>Features</h4>
<ul>
<li>Day range</li>
<li>Disable tabs.</li>
<li>Title length.</li>
<li>Count Display.</li>
<li>Excerpt option.</li>
<li>Excerpt length.</li>
<li>Category filter.</li>
<li>Display thumbnails.</li>
<li>Display recent comments.</li>
<li>Calculate visits or page views.</li>
<li>Custom field options for view counts.</li>
</ul>

Popular Widget

The plugin still works as expected but the support doesn't seem to be very responsive: Last reply on the Wordpress forum over 1 year ago, on the recommended official forum over 2 months ago.
More activity would be great since there are not many comparable alternatives.



Nice plugin, and some support would be great

Display the most commented or most viewed posts in a tabbed widget, filter the post by date range or by category. It also includes a tags tab.

Category Popular Tags vs Popular Widget