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.
toffee toff toffy doff teff tiff tofu tuff taffy tophe dieoff taffia toughie
feoffee coffee toffee fee bouffe fife coiffe gaffe piaffe pouffe ruffe waffie