Ultra rhymes with:
altra, altra, artra, astra, atra, balestra, batra, boonstra, bostra, bumiputra, chitra, cleopatra, cometra, contra, costra, dextra, dutra, dykstra, electra, elektra, extra, feenstra, hamstra, heemstra, heidstra, hiemstra, hoekstra, hofstra, hukstra, hydstra, intra, kamstra, kontra, kooistra, kustra, lastra, licitra, maestra, maitre, malhotra, mantra, matra, metra, mitra, nicotra, nostra, notre, olestra, orchestra, petra, poitra, rienstra, sartre, sentra, sinatra, spectra, spoelstra, sumatra, tatra, telettra, telstra, terpstra, tetra, tuinstra, veenstra, westra, xtra, zandstra, zylstra