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.
essays esses eses
assays resays bioassays missays essays naysays says nauseas mesas saws seas soys coseys paisas visas resaws seesaws quassias casas lyssas assais massas fossas masas sass hoseys psoas causeys misassay cassias moseys tussahs