Mailboxes rhymes with:
boomboxes, jukeboxes, matchboxes, skyboxes, boomboxes, jukeboxes, matchboxes, paradoxes, skyboxes, affixes, alex's, alexs, amax's, amex's, annexes, apex's, appendixes, avtex's, axes, banks's, boomboxes, brooks's, cevaxs, cineplex's, climaxes, coaxes, comex's, cox's, crucifixes, cyrix's, dax's, dynamics's, endotronics's, essex's, exes, faxes, felix's, fixes, flexes, gearboxes, genex's, hoaxes, imax's, index's, indexes, ionics's, isomedix's, jukeboxes, knox's, lynxes, marks's, matchboxes, matrix's, matrixes, max's, metroplexes, miramax's, nixes, nynex's, onex's, outfoxes, paradoxes, patlex's, perplexes, phoenix's, relaxes, royex's, sachs's, saks's, six's, sixes, skyboxes, sox's, speakes's, spinks's, surtaxes, syntex's, tax's, taxes', telex's, telmex's, vaxes, waxes, wickes's, x's, x.'s, x.s, xerox's, xeroxes
Mailboxes sounds like:
mailbag, mailbags, mailbox, malpass, malveaux, minilabs, molpus, molpus', molpus's, muehlebach