I have a question which has 4 different subcases or "avatars":
1) Has every "interesting" class of number been invented? 2) Has every "possible" class of number been invented? 3) Does Nature use every interesting class of number for something in the physical realm? 4) Does Nature use every possible class of number for something in the physical world?
Prime numbers, integer numbers, fractional numbers, irrational numbers, real numbers, complex numbers, quaternionic numbers, octonionic numbers, Cayley-Graves numbers, p-adic numbers, tropical numbers, surreal numbers, transfinite numbers, adelic numbers, grassmannian numbers, clifford numbers, Cayley-Dickson numbers, ternary numbers, ideal numbers, p-ary numbers, ... What else?