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.
harass harissa haars hairs horas hares hears hoars haeres horahs hearse hoarse heiress hoorays hurrays harries hoorahs hearsay harrows hurrahs hers hires horsy heirs heres hoers hours horse heros heresy heroes hirees horsey houris herries hurries
brass cuirass frass morass trass crass grass harass ras liras rase phrase buras bewrays erase arias craws boreas hurrays briss rays hoorahs praus hoorays muras norias varias serais prays sirrahs jarrahs gerahs press sierras auras derays drays sharias charas ureas yttrias tress cross torahs terais hydras duress dross suras proas douras areas eyras soras morassy horas cerias rais frays braws hurrahs bras peeress nairas rias eras terras varas koras grays forays boras arrays kaross kerrias morays gross braes lauras toras horahs paras caress brassy heiress gyrase ferias grassy raws maras brays surahs wrasse priss praos prase mbiras murras pross moras sirras cress arras surras seeress dourahs draws dress duras durras hydrase trays truss urase whereas choreas tiaras
haar hair hairy hare harrow harry hear hoar hoary hora horah