nbmblueeye

The Plugin will help you easy to add Custom Taxonomy to your Post, Custom Post Type. 
You just input the post_type and The Name of Taxonomy, 
You should tick to hierarchical option: will become Category or become Tag);
If you want to update, remove the existing taxonomy just go to page MCT_All, this page will be used to manage your added custom taxonomy
Ordered list: 
– Existing Custom Post Type Slug: the slug name from post_type, which is the one you want to add custom taxonomy 
– New Taxonomy Name: the name of Custom Taxonomy, which you want to add. will be display on the admin menu 
– New Taxonomy Slug: add the slug of the custom taxonomy, which you want to add

My Custom Taxonomy

This Plugin will be used to add custom taxonomy onto your Post, Custom Post Type

KrishaWeb

Dilip Bheda

Pratik Gandhi

Girish Panchal

This plugin gives flexibility to user to change posts from one post type to another. Also users can change posts from post type to page.
Features 
• Easy installation 
• Post to other post type or page. 
• Free support
Checkout the advanced features of Post Type Transfer: 
• It provides functionality enable/disable the feature for certain post type. 
• It also provides functionality to transfer the taxonomy while transferring the post to other post type. You can create new taxonomy or use the current one.
<a href="https://codecanyon.net/item/post-type-transfer-pro/21585540" rel="nofollow ugc">Get the Post Type Transfer Pro</a>
<h4>Supported Types</h4>
The plugin will help you to transfer any post’s post type to other post type. It will also allow custom post type. Invisible post types like revision, menu and attachment are purposely excluded

Post Type Transfer

Easy to use

A simple way to change a post's post-type in WordPress

My Custom Taxonomy vs Post Type Transfer