Frets on Fire - Bonus content.
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!
Rocksmith+ - Rocksmith builds off of the fundamentals of music games like Rock Band and Guitar Hero by offering fundamental lessons in actually playing guitar.
UltraStar Deluxe - A free and open source karaoke game inspired by the Singstar™ game, runs on Windows, Linux and macOS.
Osu - Osu is Music, Rhythm, Single and Multiplayer video game developed by Dean Herbert.
Soundfont Midi Player - Full-featured MIDI and Karaoke player/router with built-in MIDI synth