People find physical laws by a process of exploration and refinement on the basis of experience.   That’s been going on for thousands of years, and especially over the last three centuries.
			Regularities that are regular enough, and useful enough, become “physical laws.”
	Here are names for special constants of proportionality in useful physical laws: mass, density, viscosity, bulk modulus, thermal conductivity, thermal diffusivity, resistance (lumped), resistance (per unit length), inductance (lumped), inductance (per unit length), membrane current leakage (per length), capacitance (lumped), capacitance (per unit length), magnetic susceptibility, emittance, ionization potential, reluctance, resistivity, coefficient of restitution, . . . . There are many, many more.