I’m not sure if this one counts as underrated but it’s my favourite!
the music (esp the opening scenes), the dynamic between Pazu and Sheeta (Pazu is the sweetest ghibli hero imo), giant robots, ancient floating castles, the usual ghibli focus on nature, love, friendship, etc etc
oh and of course the old lady sky pirate and her band of idiot sons
another honourable mention has gotta be Nausicaä
