GSnap - With GSnap you can get an auto-tune effect.
Clownfish Voice Changer - Clownfish Voice Changer is multiple voice changing software for various chatting and gaming platforms.
Revoice Pro - Revoice Pro is an audio plugin used for vocal tuning, time correction and ADR.
Soundpad - Play sounds in voice chats in high digital quality.
CrispyTuner - Fully featured vocal tuning suite.
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.