Spiral Galaxies - Named for their shape, spiral galaxies are the most common type of galaxy in the universe. Of all the known galaxies in the universe, 77% of them are classified as spiral galaxies.
Lenticular Galaxy - A lenticular galaxy is a type of galaxy intermediate between an elliptical galaxy and a spiral galaxy.
Elliptical Galaxies - These elliptical galaxies are classified by their ovular shape and lack of central bulge. In contrast to their name, however, sometimes these galaxies are rather circular.
Barred Spiral Galaxies - Although similar to spiral galaxies, barred spiral galaxies differ in their shape slightly.
Irregular Galaxies - According to NASA, the uniqueness of irregular galaxies may be because of interactions they could have had in the past with other, neighboring galaxies.
S0 galaxies - These systems exhibit some of the properties of both the elliptical and the spirals and seem to be a bridge between these two more common galaxy types.