I've taken a list of English words, and examined each of them to see what they sound like (using the PHP metaphone function). This page lists the most common metaphone codes, along with their words. You can also search for a word of your own, and see which words sound similar - and which ones rhyme, and which ones alliterate.
hydras hydrase hydros hydrous duras draws drays douras derays durras yttrias dourahs drys dors doors dries trays doers dross tyros toras dures dares tahrs dress dorrs dorsa trass dears drees duros druse deers durrs tyres deairs terras dories dressy drowse drowsy torahs duress drossy terais derris dairies dearies derries diaries dowries durries
hydras ras jarrahs hurrahs grass auras arrays serais erase braws eras phrase norias ferias horahs hoorahs braes maras bewrays boras praos craws frass suras drys buras terais sharias hydrase charas ureas durras yttrias trass soras torahs bras moras sirrahs dourahs proas derays draws praus morays kerrias murras gerahs boreas lauras arras areas brays eyras arias grays rais duras surras sierras frays rase prays horas paras cuirass crass harass forays rias gyrase prase liras varas rays cerias hoorays drays sirras raws douras hurrays muras brass koras dors mbiras hydros morass terras nairas toras trays surahs urase whereas varias choreas tiaras
hydra hydrae hydria hydriae hydro