Standard model has a number of fundamental particles, that are defined by various numbers and species, like charge, mass, etc.

While those parameters are whole numbers or fractions, which would limit the number of simple particles, it is not clear why there is not more diversity (or more numbers, parameters, dimensions, you name it).

A uninformed guess would be that since we are made of a certain set of particles, we are effectively never in contact (i.e. never observe directly or indirectly) anything but compatible particles.

But this is not entirely satisfying, let alone because this explanation is probably not compatible with gravity or large scale phenomena.

Please note this question is not about dark matter or exotic matter or places we have not reached yet.

I am only talking about the relative lack of diversity of the particles making up our immediate environment.

Does that mean there is mathematically only a limited number of possible fundamental, if not foundational, particles?