I had experimenet with some effects from GR7, such as SOLID EQ and TRANSPOSE STRETCH, they are actually decent for changing the voice if you are voicing typical cartoony characters, monsters, demons, entities, robots etc...
But is there an ideal plugin or pitch shift effect that can just change the pitch of you voice perfectly without the grain sound and quality loss(FL Studio has that perfect pitch shift algorhythm where there is no grain and clipping effect, and plus, it also has a feature that let's you change the pitch without sounding too much like a chipmunk)?