UltraStar Deluxe - A free and open source karaoke game inspired by the Singstar™ game, runs on Windows, Linux and macOS.
Karaoke Mugen - Video & Movies and Audio & Music
Walaoke - Walaoke is the app that makes it fun to sing karaoke anytime, anywhere.
OpenKJ - Open source cross platform karaoke hosting software
Siglos Karaoke Professional - Siglos Karaoke Professional is a professional karaoke player who can make your party become more exciting.
QMIDI V2.0 - QMIDI is an open source karaoke player for Windows, Mac OS, and Linux.