Cubasis - Cubasis is Steinberg’s streamlined, multitouch sequencer for the iPad.
ReSlice - Slice your audio with an advanced, rhythmic arpeggiator and FX.
SunVox - SunVox is a small, fast and powerful modular synthesizer with pattern based sequencer (tracker).
Auxy Music Studio - Auxy brings real music creation to iPhone in a simple and inspiring format.
FamiStudio - FamiStudio is very simple music editor for the Nintendo Entertainment System or Famicom. It is designed to be easier to use than FamiTracker, but its feature set is also much more limited.
nlog Synth - Professional Virtual Analogue Synthesizer ::: check nlogmusic at YouTube :::