muffon is a desktop music browser / streaming service that retrieves info and audio/video from Last.FM, Discogs, VK, YouTube, Deezer, Yandex Music, Odnoklassniki, Spotify (partly), SoundCloud, Bandcamp, Genius and Rate Your Music. You can listen to artists, watch videos, browse tags and even listen to whole albums.
It has no ads and it's absolutely free to use.
It's built with Vue and Electron.
It's tested on Windows 10, but there are builds for OS X and Linux as well.
It's currently in alpha, so not everything's perfect and much to be done.
P.S. Unfortunately I don't know is it legal or not, but maybe you could tell me.