I used YouTube a lot in my music classroom. Usually it was to show examples of music or a concept but not usually a certain channel. Here are a couple that I used more frequently.
https://www.youtube.com/channel/UCuNYP6sYWgjAddNo534PEKQMusication is a channel that uses boomwhackers. I used this at the end of the year, or when my voice was wearing out. Also a great one for a substitute.
https://www.youtube.com/user/makingmusicfunMaking Music Fun I used for short clips about composers. Under 5 minutes is perfect for elementary students. There are also some theory lessons.
With a year of Covid, I found many channels that have been created that would help in the classroom. What a wonderful tool if we are in person or virtual. Here are some of the gems that have good content.
https://www.youtube.com/channel/UCkide6AQAr7wjc4f9xoRORghttps://www.youtube.com/channel/UCBLac7-TxLsvHPJnA0DxxRwThis is a great resource for teachers
https://www.youtube.com/channel/UCj2IP31nc3ehLU--_ze8CbQ