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.
cays gays casa kays case coys caws quays cause cassia cooeys causey kas cos gas coos keas cosy koas cuss goas kaas keys kaes coss guys cozy goys gaes cues cows cozey gauss quass cusso cosie gauzy gawsy gassy quais quasi cosey queys
ays bays shays ways says rays pays nays mays lays quays kays gays cays jays hays fays days chays yays as