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.
freest forest fairest frost first forestay furriest firriest fieriest frosty frowst frusta veriest frowsty foreside fireside foresaid frizette frisette verst farced forced frized verist verset verste farside frizzed varsity feracity ferocity
reest freest queerest crest hairiest veriest arrest eeriest fairest reset resit rest wrest wriest resat airest merriest leeriest poorest prest priest rarest searest sorest sourest dearest dourest driest teariest wariest wiriest charriest sheerest mooriest airiest barghest nearest breast burriest aeriest erst fieriest forest beeriest barest firriest furriest verst hoariest goriest leariest miriest merest preset presto purest rearrest serest sorriest surest direst drest tarriest truest weariest chariest cheeriest yarest
frees freeze reverse reveries refers referees reefers fevers feverous froes fries frieze foresee foresaw fores fires feres fares reveres revers reverso