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.
highness heaviness huffiness havens
highness roughness nighness toughness beefiness suaveness savviness evenness daphnes goofiness geophones iffiness heaviness puffiness huffiness liveness leafiness vainness fewness miffiness safeness phones sphenes finesse daffiness feyness dauphines naiveness diaphones rifeness deafness waviness