UltraStar Deluxe - A free and open source karaoke game inspired by the Singstar™ game, runs on Windows, Linux and macOS.
KaraFun - KaraFun is the best online karaoke. Over 35,000 karaoke songs, with studio quality, at home or on the go. Regular updates. Free demo!
Karaoke Mugen - Video & Movies and Audio & Music
Soundfont Midi Player - Full-featured MIDI and Karaoke player/router with built-in MIDI synth
Smule - Smule is the social singing app that lets you enjoy millions of karaoke songs. Connect with your friends from all over the world or sing with top artists!
vanBasco's Karaoke Player - vanBascos Karaoke Player plays MIDI Karaoke files. Lyrics can be displayed in full-screen.