The YouTuber Peter Barber is one that says: "Of course I've heard this before; you're here for analysis" (He's a professional opera singer), mixed with a bit of theatrical reactions.

Elizabeth Zharoff (Channel name: "The Charismatic Voice") is another professional opera singer (and vocal coach) who does more intellectual reactions. And she'll also often comment on how certain sounds are created, physically, and whether a singer is performing in a healthy way, or threatening damage to their vocal folds.