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.
grads grades gradus grids greeds groats grides grates guards gratis greats gourds gourdes corrades cords grots cards curds creds grits cruds carats kraits greets kurtas grouts creeds crudes griots crates crowds krauts cairds korats karats credos garrets creates karates carates curates grottos garotes cardias caritas garrotes corodies corridas keratose corrodes crowdies garottes grottoes queridas corrodies garrottes
rads brads farads grads korats lairds hordes jerrids frats grades herds cards irades reds rods cruds shreds nards chords cairds marauds turds gourdes murids drats bards gradus rereads brats weirds yards shards charades wards treads hydrids derats sarods prods parados nurds liards bardes aortas tortas sords perdus girds guards byroads roads boards birds beards oreads fiords fards hairdos sherds karats hurds dorados corrades hoards triads lords burds chards myriads hybrids raids pards breads hards reads sciurids rids frauds broads tirades kurtas lards purdas braids weirdos rats ordos gourds curds creds cords carats grids jurats merdes jerids irids fords yairds readds nerds parades prats sards surds dreads trades urds words shairds yirds
grad grade garda gardai grat grate great grid gride groat grody