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.
miffier mover
huffier chaffier buffier iffier chuffier puffier miffier daffier duffer differ beefier fiery goffer reefier chaffer niffer puffery piaffer puffer reoffer zaffer affair defier chauffer chuffer deifier quaffer buffer chauffeur zaffir gaffer gauffer feoffer suffer goofier reifier coffer fifer coiffeur offer leafier deffer doffer whiffer kaffir fiver fer fir