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.
drat derat derate dart dirt hydrate trait dread treat dirty deaerate dorty droit treaty dorado diorite tret trot tart trad tort dared dreed druid dured tarty torot torta torte trade droid dried tarot trite trout
rat brat frat jurat carat grat karat korat prat derat drat