Eras adjectives are listed in this post. Each word below can often be found in front of the noun eras in the same sentence. This reference page can help answer the question what are some adjectives commonly used for describing ERAS.
bygone, certain, different, distinct, earlier
early, geologic, geological, great, historical
important, later, long, major, many
modern, new, other, particular, past
previous, prior, respective, roman, several
subsequent, successive, various
Hope this word list had the adjective used with eras you were looking for. Additional describing words / adjectives that describe / adjectives of various nouns can be found in the other pages on this website.