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.
gown gone goon goony gonia goanna gooney goonie gan con gun gaen kaon coni conn coin cone guan gain cony gane coon gaun koan coign coney guano gunny koine quoin
gown lown mown known own sown down town shown on