Distribution of the mass fraction of kinematic structures in TNG50 galaxies. The sum of the bar heights is normalized to 1. We then classify galaxies into tiny-halo galaxies, halo-subdominated galaxies, and halo-dominated galaxies by f_halo ≤ 0.2, 0.2 < f_halo ≤ 0.5, and f_halo > 0.5, respectively. The criterion f_halo = 0.2 and 0.5 are marked by the black vertical lines. The mass fraction of spheroids f_spheroid is equal to f_bulge + f_halo. From top to bottom, we show the galaxies with stellar mass log (M_⋆/M_⊙)∈[10⁹, 10^11.5]. The galaxies with log (M_⋆/M_⊙)∈[9.5, 10.5] are the most representative sample.