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.
grass grassy gross crass grays grease greasy gars cuirass curassow carassow cress gorsy grows grees guars graze gorse gaurs gurus koras grues cross craws gores greys goers grace kaross crosse crease creasy grouse caress guiros cressy crissa gurries kerrias cars cors cris crus curs kirs kors kris
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