iOS Musician Apps (146) Supported Technologies is Inter-App Audio (IAA), Instrument Sounds is Keyboards

Electric Vintage is a virtual instrument based on a reproduction of a famous vintage electric piano (1976).

LCW-2 mono is a little complicated synthesizer based on ToyTone and implements several experimental functions.

Laplace is a physical-modeling synthesizer based on resonator synthesis that makes it easy to create bowed string, plucked string, blown pipe and metallic sounds.

KinderKlavier is a realistic toy piano instrument for iPad, iPhone, and iPod Touch.

We painstakingly sampled the sound from every key and button of an authentic 1960’s electric chord organ to bring this timeless instrument to your device.

Mimicking the layout of Hohner's iconic chromatic button accordions (CBA), both B-System (Bayan) and C-System, this intuitive virtual accordion is easy to play and sounds exactly like the real instrument.

Virtual Analogue Synthesizer.

Englitina is an authentic-sounding English Treble Concertina for the iPad.

Tines emulates an electric piano.

Shape is a polyphonic synthesiser allowing the user to draw the shape of the oscillator waveform.

Multilevel Interactive Sound Synthesizer. Up to 240 Frequency Modulation Oscillators or simple Wavetable Additive.

Agonizer is a monophonic synthesizer designed in collaboration with YouTuber and synth bass expert Jakob Haq of haQ attaQ

A Simple Ad-Free Piano-like Musical Keyboard. Easy to Play, Good Response and Small Application Size. Just Play the Instrument. The app doesn't use sampled real sounds but use FM synthesis. It sounds like piano though it's false.

AudioKit Synth One is a completely free & open-source professional iOS Synthesizer. 

FM TiNES is an electric piano library dedicated to the most beautiful FM electric pianos ever made.

Professional Virtual Analogue Synthesizer.

Free iPad instrument featuring the classic sounds of famous 80s FM Synthesizers.

The Moog Model 15 App is the Moog modular synthesizer and synthesis educational tool.

The Minimoog Model D App is a mobile transmutation of the world’s first portable synthesizer, the Minimoog Model D®.

Moebius Lab is a multimorphic sound processor which contains a synth, a varispeed stereo sample player, effects and LFOs that can modulate each parameter.