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.
relax rouleaux relics relocks relooks reliques
relax lax flax flaxy helix galax galaxy poleax poleaxe rouleaux telex
relic relique reliquiae relock relook