The discovery of neutrino oscillations requires an extension of the Standard Model that generates neutrino masses and mixing. One of the simplest possibility is the addition of right-handed neutrinos which are fermionic gauge singlets. Low-scale realisations of this idea have a very rich phenomenology and their experimental signatures can be strikingly different depending on the masses of the right-handed neutrinos. We will discuss here two examples of processes where heavy sterile neutrinos can leave a visible imprint. Below the GeV scale, they can modify kaon decay properties while above the TeV scale they can induce large corrections to the triple Higgs coupling. These observables can then be used to constrain neutrino mass models or probe them in a regime otherwise difficult to access.