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.
treater treader triter trader tarter tartier trotter traitor tireder troutier toreador trattorie trattoria darter tartar tardier hydrator torrider deaerator dirtier tartare torture
greater treater ureter tarter ferreter treader darter perter narrater krater ratter reader barrater barter prater frater irater fretter carter crater creator garter grater greeter quarter pearter rater charter
treat treaty tret terete trait tread strata strati stretta strette stretti stretto