Voxal - Modify your voice in any application that uses a microphone. From girl to alien, the voice options for online video games, avatars and podcasts are limitless.
GSnap - With GSnap you can get an auto-tune effect.
Autotalent - To make music
Celemony Melodyne - Celemony Melodyne is the perfect quick and easy tool for all your tuning needs.
FL Studio - Image-Line's FL Studio, now on it's 12th version, is a well-known music production suite and the most popular beat processor on the market, due no doubt to its longevity. Read more about FL Studio.
Revoice Pro - Revoice Pro is an audio plugin used for vocal tuning, time correction and ADR.