The short answer is: . Waves Audio is a commercial software company, and Waves Tune Real-Time is a paid proprietary plugin.
A classic that has stood the test of time, GSnap is a free VST effect that corrects the pitch of monophonic sources. It's a favorite among users of older DAWs and budget setups. waves tune realtime plugin free top
Robust MIDI control capability. You can feed MIDI notes into it to force the vocal to follow an explicit melody line. The short answer is: