I don't know about favorite ever, but I've discovered Harry Mack freestyling about a year ago and have spent dozens of hours catching up on the entire backlog, this man is a genius (and this is not a music style I even care for) . This particular video is my favorite of his due to the infectious beat and sheer positivity: https://youtu.be/dxYah-Tlkmc. Everything he does is an instant classic though.