Kymatica developer Jonatan Liljedahl has released a tone/drone generator simply titled, The Oscillator!
The Oscillator iTunes Description:
Simple and elegant tone generator with two Oscillators and one Noise generator, each with individual lowpass filters.
Use it for testing purposes or to make old-school electronic drone music.
All three modules have amplitude control and lowpass filter. The oscillators can produce one of four waveforms: sine, triangle, sawtooth and square.
Supports Audiobus: Stream the audio output in real time into other audiobus compatible apps!