iOS Musician Apps (145) Supported Technologies is Audiobus, Instrument Type is Synth

PixelWave is an experimental synth with old school pixel interface.

Xynthesizr is a streamlined yet capable 32-step matrix sequencer/monotimbral synthesizer with generative features and MIDI.

Fractal Bits is a drum synth with over four billion unique sounds created by fractal algorithms.

miRack is a Eurorack-style modular synthesizer. It aims to provide user experience and audio quality close to those of the real Eurorack hardware.

Groove Rider GR-16 is a professional step-sequenced groove box, inspired by professional hardware drum machines and rhythm boxes.

The BLEASS sidekick AUv3 is the world's first iOS AUv3 effect plugin that offers a kick drum synth and sequencer coupled with a sidechain compressor in order to bring unique and creative dynamics to your music!

SunVox is a small and fast cross-platform modular synthesizer with pattern based sequencer (tracker).

BLEASS Granulizer generates short samples (‘grains’) from different input signals by modulating different parameters which you can visualize thanks to a 3D Visualizer.

TweakyBeat is a drum machine synth.

Waveshaping Synthesis is a type of distortion synthesis that can create dynamic spectra in a controlled way.

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

Hexaglyphics is a 13-bit noise generator with an interface based on an original alphabet for hexadecimal values.

Pure Acid is a bassline synthesizer and drum machine in one app.

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

SoundScaper is an experimental sound mini lab for creating unusual soundscapes, atmospheric textures, drones, glitches and noises based on circuit bending principles.

Crystal Synth XT is a full featured semi-modular synthesizer, ideally suited to creating lush evolving soundscapes.

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

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

Syntorial is a synthesizer training app, that will teach you how to program synth patches by ear.