- Water/Rock/Steel/Ground/Ice would all be under states of matter which sound transfers trough rapidly and at a large lengths (periodicity). Factor in oscillation frequency, and you have a really destructive force. Unfortunately/fortunately, irl sound just doesn't have the potential to deal this much damage to these associated types, sans maybe Ice due to avalanching. You would need a much stronger force for these things to fail under oscillation potential, i.e. wind gusts, earthquakes, etc. But in the world of video games where lizards breathe fire, and Anubis is made out of Steel, sound would kill!
- Electric-types would be hit super effectively due to sound on the line causing massive disturbance in electrical potential. Noisy electricity is notorious for causing machines to behave erratically, and causing disruption in general.
- Since Flying-types are associated with "air", sound travels mediocrely through air since the particles are further apart than they would in a solid or liquid. This is also the reasoning for Ghost-types; they're lacking in material and therefor wouldn't be affected as much by Sound (so far this is pretty true via normal sound-based moves like Hyper Voice, Round, etc.). Forests are places of trees, which provide obstruction to sounds and also plants have roots to dissipate the energy of sound, so Grass-types would be resistant to sound-moves.
- Sound waves cancel out other sound waves when played at inverted frequencies (the relationship of sound and noise cancelling), and is the only thing I can think of that would be super effective against the Sound-type. I know that's unbalanced, but then again, what would sound types be immune to or even resist? Probably nothing. So you really just have an offensive type like Ice that has fewer resistances to than advantages for.