*Disclaimer: New music apps come out every day, which makes this page impossible to keep up to date. Sorry!
Mynotegames
KinderBach
$$ Tenuto
Loopseque
GrooveMaker
Table Top
Launchkey
Launchpad
Sample Tank
$$ Touch OSC - Midi Controller
Smule Magic Piano
Raindrop
VoicePlus
VidRhythm
QuickVoice
Tempo Slow
Pro Metronome EUM
Spin Tuner
n-Track Tuner
SoundHound - Can tell you what song you're thinking of or listening to
Songza
Pandora
Band of the Day
DJ Mixer Pro
Shazam
Virtuoso - Piano
Perform
Etude
Tonara