What operas do you like that are little-know or you considered are underrated? And also what operas do you think deserve to have more recognition?
My favourite CD recording:Die Tote Stadt by Erich Wolfgang Korngold might fit this category. Aside from the ubiquitous Mariettes Lied, I think the opera itself has been somewhat underrated and deserved more than the one (afaik) recorded version that was available for a long time. I suspect that this might be changing as I've learned that there is a new recording out there.