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.
sixte sixty sext sexed sexto sicced sickest sagacity saggiest soggiest suckiest zygosity sequacity
sixte luxate dixit sixty requisite nixed mixt mixed quixote coesite fixt fixit fixed fixate bauxite axite taxite