The question, broadly, is how many elementary particles do you expect to be in the final theory. But just to be more concrete, I have narrowed it to "fermions" as Pauli principle is the closest thing we have to ancient "impenetrability", fitting the naive idea of particle.
Well, in part because when you are thinking about the question you think about "degrees of freedom" of fields, and this usually come to duplicate or halving the answer. For instance, if you decide that particle and artiparticle are two different elementary objects, you multiply by two. If you decide that helicities 1/2 and -1/2 are the same particle, you divide by two. So the likeliest answer will be something as n*2^m... note that by restricting to fermions I ruled out the number of Higgses and other bosons. Then, as always, the poll does not cover all the possibilities. Reasoned comments are wellcome :-) Alejandro
six leptons and six quarks, plus antiparticles, makes 24. I don't consider "fermionic" particles in super symmetry to be real fermions.