OFFICIAL PAGE: Spleeter
Spleeter is a free open-source sound source separation application from Deezer Research. It comes in the form of a Python Library based on TensorFlow, with pretrained models for 2, 4 and 5 stems separation. It is a command line application so there is no GUI (graphical user interface). Several web-based interfaces for Spleeter are currently available at moises.ai, Ezstems, Splitter, and melody.ml.
Screenshot courtesy of Deezer Research