In the domain of time and pitch, ReVoice Pro from SynchroArts is a bit of a secret weapon, not only does it have the ability to manipulate audio the time and pitch domain, to correct timing and pitching of a take, but you can also take a master corrected track to create highly editable double tracks and also to turn those into additional harmonies. Really handy for creating harmony section from a couple of takes of a lead vocal. But its not only limited to vocals..
ReVoice Pro is currently on sale at 30% off till November 21st via the Synchro Arts Website
Affordable workstation type keyboard