Documentary adjectives are listed in this post. Each word below can often be found in front of the noun documentary in the same sentence. This reference page can help answer the question what are some adjectives commonly used for describing DOCUMENTARY.
bbc, best, first
hour, length, long
minute, new, part
recent, short, video
Hope this word list had the adjective used with documentary you were looking for. Additional describing words / adjectives that describe / adjectives of various nouns can be found in the other pages on this website.