Magic Playlist - Get the playlist of your dreams based on a song
Keras - Keras is a minimalist, modular neural networks library, written in Python and capable of running on top of either TensorFlow or Theano.
Spotalike - Spotify playlist with similar songs, according to Last.fm
TFlearn - TFlearn is a modular and transparent deep learning library built on top of Tensorflow.
Playlist Machinery - Tools that help you create & organize your Spotify playlists
Clarifai - The World's AI