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.
grippy gripy gripey grippe grip grapy gripe grapey crappy grappa gorp grope group crepy grape cripe creepy crepey croupy crappie croppie groupie
drippy grippy trippy crappy gripey grippe gripy preppy chirpy