Stephanie Leary

This is a utility for converting lots of posts or pages to a custom post type (or vice versa). You can limit the conversion to posts in a single category or children of specific page. You can also assign new taxonomy terms, which will be added to the posts’ existing terms.
This plugin is useful for converting many posts at once. If you’d rather do one at a time, use <a href="https://wordpress.org/extend/plugins/post-type-switcher/" rel="ugc">Post Type Switcher</a> instead.

Convert Post Types

Wordpress 4.9.5

No better plugin for converting categories to custom post types. And vice versa.

Still works great

A bulk conversion utility for post types.

Amaury Balmer

WordPress 3.1 and up allow to manage new custom post type, this plugin makes it even simpler, removing the need for you to write any code. Excerpt update your theme !
This plugin provides a nice interface and easy access. The plugin provides almost all the parameters of the WordPress CPT API.
It’s possible to manage the permissions of custom post types such as articles or pages. Or create a full set of custom permissions and related roles !
This plugin is developped on WordPress 3.3, with the constant WP_DEBUG to TRUE.

Simple Custom Post Types

WordPress 3.1 and up allow to manage new custom post type, this plugin makes it even simpler, removing the need for you to write any code.

Convert Post Types vs Simple Custom Post Types