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.
treader trader treater tireder toreador tardier torrider triter tarter tartar tartier traitor trotter troutier deaerator trattoria darter derider dirtier tartare torture
reader treader shrewder warder broader larder greedier readier redder reedier boarder braider breeder raider parader forrader herder hoarder carder grader greater guarder marauder tireder trader harder toreador treater shredder yarder
tread trad dread tared teredo tirade tired trade treat treaty treed triad tried trued tyred