Rarity adjectives are listed in this post. Each word below can often be found in front of the noun rarity in the same sentence. This reference page can help answer the question what are some adjectives commonly used for describing RARITY.
comparative, considerable, excessive
extraordinary, extreme, great
greater, greatest, increasing
real, relative, such
true, utmost, very
Hope this word list had the adjective used with rarity you were looking for. Additional describing words / adjectives that describe / adjectives of various nouns can be found in the other pages on this website.