What is the best, most complete API or database for searching music data in 2018?

I'm looking for service which provide short info about song, artist, album. I'm not interested in music files, I need just simple info about track. Some ov services I 've been found through search:

• RoviCorp http://developer.rovicorp.com . Probably the best service, but looks like it doesn't work anymore. I created new app for development purpose few days ago and it is still unavailable for testing;
• SoundCloud. Stopped to register new apps;
• Spotify. The problem is - I can't find info how much requests I can send per day/month.
• Last.fm , didn't find info about rate limits

I need service which is still actual in 2018, has some free requests for non-commercial applications