GForce Software's latest release - based on the lowly but highly regarded mono synth the Arp Axxe, which had 1 oscillator, one filter, one LFO and 1 ADSR.
The Axxess is somewhat enhanced.
Firstly you get 6 voice polyphony, FX in the form of distortion, delay and reverb, plus an additional sub oscillator and of course the GForce XMOD additions - essentially a dedicated X-LFO and X-ENV for pretty much each parameter. This expands the capabilities significantly.
@TimCant takes a look at the new instrument - which is available now priced at $99 (note the introductory offer has ended)
https://www.gforcesoftware.com/products/axxess/
Developments for Korg's instrument have been slow but promising.