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.
peon peony paeon pen pony pone pein peen pion pean poon penni penna paean penny penne pennia pennae pin pan pun hyponea piny pian pine pina pain hyponoia pane puna pawn puny panne piano piney pinna pinny punny
aeon eon jeon neon paeon peon en on