I think it would be pretty nice if more filters can be added to the advanced search, for example:

-Bands with at least one full album
-Bands with at least one review

I know this one is hard but it would be awesome:
-Bands that sing in a certain language

Not currently feasible, since such information is not systematically marked. Meaning sometimes there is a mention about a band's choice of language (obviously most often as pertains to their lyrics) in the additional notes, but a) feeding those instances into the adv. search would create a lot of false positives and b) it's not consistently done by a long shot.

A field for languages has been suggested before, though, and it is part of a long list of requested features in the staff-only forum (note that this does not guarantee actual implementation).

What about an advanced search for users? Based on country, age, favorite genres etc.

That seems rather, err, inappropriate? We're not Metal Facebook. In any case, the advanced search is a tool for the database proper and user profiles are not part of that but rather of the system maintaining it.

Got it. Thanks.

Thank you for the answer!

Are my first two suggestions going to be considered? Just asking.