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.
grapy grapey gripy grape crappy grippy grappa gripey crap gorp grip crape group gripe grope crepy creepy crepey croupy grippe crappie groupie carp crop
grapy rap chirrupy charpoy drapey syrupy serape rewrap rape reap ropy wrap bewrap frap harpy crap crape crappy crepy grape grapey gripy sarape sirupy drape trap chirpy sharpy