CasterSoundboard - A soundboard for hot-keying and playing back sounds. (For podcasting)
Mixxx - The most powerful free DJ software in the world.
JN Soundboard - An open-source hotkey soundboard program
Guitarix - Guitarix is a simple Linux Rock Guitar Amplifier for https://alternativeto.
Soundplant - Play sound files with the computer keyboard
VirtualDJ - Virtual DJ Software - MP3 and Video mix software for DJs