Portal adjectives are listed in this post. Each word below can often be found in front of the noun portal in the same sentence. This reference page can help answer the question what are some adjectives commonly used for describing PORTAL.
arched, based, central, dark, eastern, first, front
gloomy, golden, gothic, grand, great, high, large
lofty, low, magic, magnificent, main, massive, narrow
new, north, online, open, outer, sacred, same
single, small, south, southern, very, web, west
western, wide, wondrous
Hope this word list had the adjective used with portal you were looking for. Additional describing words / adjectives that describe / adjectives of various nouns can be found in the other pages on this website.