Right handed neutrinos with Majorana masses below the electroweak scale can simultaneously explain the observed neutrino oscillations and the baryon asymmetry of the universe in the minimal type-I seesaw model. They can be searched for at existing or proposed experiments, including LHCb, BELLE II, ATLAS, CMS, FCC-ee, CEPC and SHiP. The corner in parameter space where lepton number is approximately conserved and the mixing with electron flavour is small turns out to be interesting from a cosmological as well as experimental viewpoint. It remains to be seen how this can be motivated from a top-down approach, and whether there may be a connection to the active neutrinos flavour puzzle.