GSnap - With GSnap you can get an auto-tune effect.
Linux Show Player - Sound player designed for stage productions
Revoice Pro - Revoice Pro is an audio plugin used for vocal tuning, time correction and ADR.
QLab - QLab, Live show control for Mac OS X.
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.
Trigger Audio and Video Playback - Audio and video cue player for broadcast and live performance.