How many distinct distortion sounds are there really out there ?

[Mark Hammer]

Again, let's differentiate between how many distinct designs there are, and how many readily differentiable sounds there are.

Good point Mark, you have a way of whittling the ideas to the core!

I suppose there's clippers, wave shapers, wave folders.

Mitch, there is an infinite number of ways to degrade the fidelity of an audio signal.  Some are not especially musically useful or valid, but in an era of noise pedals, that number keeps dwindling.