Ultra's rhymes with:
artra's, astra's, chitra's, cleopatra's, contras, contras', extras, matra's, orchestra's, orchestras, petras, pietras, sinatra's, spectra's
artra's, astra's, chitra's, cleopatra's, contras, contras', extras, matra's, orchestra's, orchestras, petras, pietras, sinatra's, spectra's