Higgs mode (collective amplitude mode) in superconductors, recently detected and analysed in a conventional, s-wave superconductor, opens a novel avenue for probing the U(1) symmetry broken state. Now we have extended the notion to an unconventional, d-wave high-Tc cuprate, where a characteristic third-harmonic generation hallmarks the d-wave superconductor in a space-group resolved manner. We can also predict unique features in Higgs and Leggett (phase) modes if we turn to multiband superconductors. K. Katsumi et al, PRL 120, 117001 (2018). Y. Murotani et al, PRB 95, 104503 (2017).