However, none of these digital operations can, in a reasonable amount of processing time, thus far, emulate the infinite-series complexity of true analog distortions.
So all the waves, Slate VCC, etc. are all using the same algorithms (no matter what they say on their marketing speak), just tweaked in slightly different ways (which is where the real point of difference is; who can do the better job of making a result as artistically pleasing as scientifically/mathematically pleasing), but, fundamentally they are all the same, all an approximation, and all not really doing what is going on in an analog system at all.
The closest thing I've seen is the Diagonal Volterra Kernels in the Nebula plugin by Acustica Audio, HOWEVER, these are still heavily order-limited, and hence I believe are still only able to create distortions up to about order 7.