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.

vlad.olaru

pixelgrade

George Olaru

Andrei Lupu

Razvan Onofrei

cristianfrumusanu

With <a href="https://github.com/pixelgrade/pixtypes" rel="nofollow ugc">PixTypes</a> you can allow your theme to define what custom post types or meta-boxes should be active when your theme is up
Note: This plugin is addressed to developers, it doesn’t do nothing if it isn’t <a href="https://github.com/pixelgrade/pixtypes#pixytpes_config" rel="nofollow ugc">properly configured</a>.

PixTypes

A WordPress plugin for managing custom post types and custom meta boxes from a theme.

Convert Post Types vs PixTypes