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.

Fastmover

Travis Pflanz

Recent Popular Tags WordPress plugin allows the administrator to display the most popular recently used tags by post authors.
This plugin is very valuable for current events websites because it gives admins the ability to set the number of tags to display and how many days to consider as “recent”… No more popular tags displaying from two years ago!
Default Usage
Heading and Recent Popular Tags will be displayed beneath each blog post.
Shortcode
Use shortcode <code>[recent-popular-tags]</code> to display Recent Popular Tags anywhere in blog posts, pages, custom post types or in a text widget.
Template Tag
Use <code><?php if ( function_exists('rpt_display_content') ) { echo do_shortcode('[recent-popular-posts]')} ?></code> to display Recent Popular Tags in your template files
Widget
Use <code>[recent-popular-tags]</code> in a “Text” widget to display Recent Popular Tags in a sidebar

Recent Popular Tags

Very useful plugin, I like how it shows more relevant tags than just a bunch of rarely used ones.



Must have for displaying tags!

Display the most popular recently used blog post tags on your website. Valuable for website with current events... No more old tags!

Category Popular Tags vs Recent Popular Tags