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.
dragon dragoon tarragon trigon trogon dracaena darken
dragon tarragon paragon jargoon trigon dragoon perigon orgone gorgon jargon jargony fourgon forgone foregone argon racon trogon
drag draggy drake dreg dreggy drogue drug druggie druggy