I don’t know if you have ever watched a high school musical. There are several male and female duets in it that are quite good, with beautiful voices.

Otherwise I’m basically I can only think of the nearest one.

As for the light music, Joe Hisaishi’s music is pretty good, but it’s just the soundtrack. There is also Bandari’s, which is especially recommended. Pictures like "Misty Forest", "Wonderland", and "Border of Glazed Lake" are all great. There are also classical ones, Chopin’s nocturnes, etc. are all good.

Piano music: summer Joe Hisaishi

Guitar music: Castle in the Sky Joe Hisaishi