The two-dimensional (2D) materials with coexistence of Dirac points and Van Hove singularities (VHSs) provide a promising platform for seeking topological superconductivity or ferromagnetism at high critical temperatures. However, ideal examples combining electronic topological properties with superconductivity or ferromagnetism are scarce. Here, through structural search, we identify 2D ${\mathrm{Sc}\mathit{X}\mathrm{S}}_2$ ($X$ = Rh, Ta, Mo) monolayers with simple square or rectangular lattices, where VHSs lie near Dirac points close to the Fermi levels. Using first-principles calculations, Bardeen-Cooper-Schrieffer theory, and Monte Carlo simulations, we found that all the three monolayers exhibit nontrivial topological electronic properties. Moreover, ${\mathrm{ScRhS}}_2$ is intrinsically superconducting with Tc = 1.36 K; ${\mathrm{ScTaS}}_2$ shows tunable superconductivity reaching Tc = 2.21 K under 6% uniaxial tensile strain which also displays ferroelasticity induced by the Jahn-Teller effect; and ${\mathrm{ScMoS}}_2$ hosts a topological ferromagnetic half-metal ground state with a giant anomalous Hall effect and Curie temperature of 329 K stabilized by a high magnetic anisotropy energy of 1.837 meV/Mo. These results establish ${\mathrm{Sc}\mathit{X}\mathrm{S}}_2$ monolayers as a versatile 2D material family for exploring exotic mixtures of topological states, superconductivity, and half-metal ferromagnetism, offering potential for novel electronic and spintronic applications.

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• Edge states
• Electronic structure
• Magnetism
• Superconducting phase transition
• Ferromagnets
• Topological materials
• Two-dimensional electron system
• First-principles calculations