For a different Natural Language Playlist alternative, you could also check out PlaylistAI. This AI-based service, available on Spotify, Apple Music and Amazon Music, offers features like smart recommendations based on your behavior and mood, playlists generated by typing in a description, and personalized favorites. It also has some different tricks, like generating a playlist based on a festival poster and blending genres by BPM.
Another option is Playlistable, a service that's closely integrated with Spotify and that uses a person's preferences, mood or favorite artists to create a playlist. It's got features like Song Match and Artist Match, and you can customize playlists to start from scratch or expand on existing preferences. You can save playlists to your Spotify account, and there's a free trial that lets you create up to two playlists.
Both of these alternatives offer powerful AI-based playlist generation abilities, so they're good choices if you want to explore new music based on subtle characteristics and cultural factors.