Here are the twenty demiregular tilings, or 2-regular tesselations.
In addition to the five symmetry groups represented among the Archimedian tilings, p4m, p6m, cmm, p4g, and p6, the symmetry groups pmm and pgg are also represented.
Just as there are 11 tilings of regular polygons with one vertex type, and 20 tilings of regular polygons with two vertex types, there are 61 tilings of regular polygons with three vertex types, the 3-regular tilings.