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.
frat fret frit fart fort ferrate forte fraud fruit farad forty fritt ferity fruity ferret forrit fretty faraday ferrety ferrite phorate variate fard ford vert fared fiord fired fordo freed fried vertu virtu
rat brat frat jurat carat grat karat korat prat derat drat