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.
riotous riots rotos rots roods routs rotes writs rotas roots rites rotis ratos radios rottes riatas writes radius rodeos raitas retuse routes roadeos rets ritz rods rats rids ruts rodes raids rudds rates ritzy rides redos roads reatas redias redoes reties readies roadies rowdies
riotous beauteous duteous rotos pottos ottos fatuous foetus photos vodous iodous touse kotos kotows lotos lottos lotus luteous mottos nodous piteous coitus setous touts