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.
fir fiar fire fair fairy fiery firry fry far feirie fer for fro fur free fury faro fear vier fare frae four fere fore froe vair fora frow fray ferry faery furry feria feuar foray vireo faerie farrow feriae forwhy furrow