exequy, equinox, quixote, exequial, exequies, quadplex, quincunx, quixotes, quixotic, quicotry, equinoxes, exchequer, exquisite, quixotism, exchequers, exquisites, quadplexes, quincunxes, quicotical, quicotisms, quixotries, exquisitely, quincunxial, quixotically, exquisiteness, exquisitenesses
These are the Q+X words that are known to exist.