Adventurer's Guide:
Buffs help to ease the impact if you're hit while making your own attacks more effective. The following buffs can be used by all classes.
Horn Melody Lv1/Drum Melody Lv1
Pipe Organ Melody Lv1/Guitar Melody Lv1
Prevating Sonata / Daring Sonata / Refreshing Sonata
Now, this is important. There are special buffs for each class that are not shared.