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.
gripy grippy gripey grip grapy gripe grippe grapey gorp group grape crepy cripe grope grappa crappy creepy crepey croupy groupie carp crap crop
gripy rip chirrupy charpoy tripe drippy ripe ropy euripi harpy crepy cripe grapy grip gripe gripey grippy sirupy syrupy drip trip trippy chirpy sharpy