Cubasis - Cubasis is Steinberg’s streamlined, multitouch sequencer for the iPad.
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.
MOTU Digital Performer - Get inspired, then refine your mix — all in a singular workflow.
SunVox - SunVox is a small, fast and powerful modular synthesizer with pattern based sequencer (tracker).
iMaschine - iMASCHINE puts professional groove production in the palm of your hand.
NanoStudio - NanoStudio is a recording studio for iOS, OS X and Windows.