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.
roupily ropily reply replay ripely ripply reapply repel rappel repeal repoll ripple
roupily pily happily huipil loopily nippily peppily pupil ropily sappily soapily supply dopily choppily ply
roup roupy rupiah croup croupe croupy group groupie troupe