Subset adjectives are listed in this post. Each word below can often be found in front of the noun subset in the same sentence. This reference page can help answer the question what are some adjectives commonly used for describing SUBSET.
appropriate, arbitrary, best, cell, certain, closed, compact
connected, convex, defined, dense, different, distinct, empty
finite, first, important, large, limited, narrow, new
nonempty, open, other, particular, proper, random, relevant
representative, restricted, same, second, significant, small, smaller
special, specific, tiny, unique
Hope this word list had the adjective used with subset you were looking for. Additional describing words / adjectives that describe / adjectives of various nouns can be found in the other pages on this website.