Korg Gadget - best music app of the last few years. Korg keeps updating it adding new features and new modules.
Cubasis 2 - one of the best full featured iOS DAW for a bargain price. Recently updated Channel strip and support of AU makes this app closer to professional desktop-class DAWs
[appstore id= 583976519] 583976519
KORG ARP Odyssei - one of the latest additions to the KORG apps family and one of the best sounding iOS synths.
[appstore id= 1147432809]
Elastic Drums - most fully features drum machine/sampler apps.
[appstore id= 817419955]
MIDI Designer PRO - flexible and customizable MIDI controller with tons of templates for various software and hardware synths.
[appstore id= 492291712]
AUFX:Space - whatever genre of music you are in - you need reverb. And this app is one of the best available iOS reverbs
[appstore id= 665650685]
KORG Module - best sounding classic instruments - piano, electric piano, organ
[appstore id= 932191687]
Modstep - this app can do so many things... it is hard to explain in one sentence. It is MIDI controller and sequencer, sampler, host for your synths... and almost complete studio that reminds me Ableton Live with many things. You should definitely try this app if you have not yet.