The least common shape for a galaxy is
cluster. Galaxy, by definition, is an arrangement composing of stars, planets,
gasses and everything more that can be seen in the space. There are three types
of galaxies and they are elliptical, spiral and irregular. Spherical could be
applicable as elliptical if you got to choose only one on the choices above.
Example of spiral galaxy is the Milky Way galaxy where our Solar system is
currently located according to the scientists. The considered satellite for
Milky Way is letter D: Copernican Dwarf Elliptical or Sagittarius Copernican
Dwarf Elliptical.
