Massive objects have sufficient gravity to overcome their own rigidity and usually have an oblate ellipsoid shape.
However, minor moons or small solar system bodies are not under hydrostatic equilibrium.
Furthermore, some of gravitationally rounded objects may have a tri-axial ellipsoid shape due to rapid rotation (such as Haumea) or unidirectional strong tidal forces (such as Io).
[1] Equidistant map projections of a triaxial ellipsoid were developed by Paweł Pędzich.
[3] Equal-area cylindrical and azimuthal projections of the triaxial ellipsoid were developed by Maxim Nyrtsov.