The Foobar2000 Playlist Organizer component allows playlists to be organized into folders.

1. Install the foo_plorg component
2. Add a new panel or tab, then add Playlist Organizer

Importing playlists using foo_plorg and foo_playlist_revive

1. Install foo_playlist_revive
2. Drag playlist files and drop on the Playlist Organizer panel
3. Select Edit > Revive Dead Items

Note: The imported playlist will have the same name as the original playlist filename.

Resources:

Website
Documentation – Hydrogenaudio
foo_playlist_revive – Hydrogenaudio
Foobar2000 – How to install a component