Tape It - App for songwriting & audio recording.

SongTrivia2.io - Songtrivia2.io is a browser and mobile blind test game that allows you to play in real time with your friends or against strangers. Several musical themes, difficulty and game modes are available to create lots of different musical quizzes.

Songcraft.io - A platform for songwriters to write, organize & collaborate.

Songlio - Free musical guessing game: race friends to name that tune

RiffShare - Write down a musical riff, send to band members, collaborate

Rock On! - A song pop adventure - music trivia awesomeness