Revisiting empirical relations in Table 5 for stars with [Fe/H] values published in the literature. Top left: L_{VOSA, BT − Settl CIFIST} vs. M_J. Top right: BC_G vs. G − J. Bottom left: M_G vs. G − J. The blue dashed lines in the three panels represent new 3-, 4-, and 3-degree polynomial fits, respectively. Bottom right: G − J vs. spectral type. The grey circles represent the mean values with a symbol size proportional to the sample size in each type.