by Ken Dirschl on WordPress.org
Automatically create menu items for your custom post types in your chosen menu and parent menu item.

Custom Post Type Settings page. Choose at least one.
Custom Post Type Auto Menu allows the user to choose a custom post type, a menu, and a menu parent item to which new custom post type posts
will be added automatically. This simplifies the menu process for users who may not be comfortable adding items to menus, or
for sites that have a large number of custom post type additions, such as products.
The plugin supports multiple custom post types.