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.
crag craggy creak croak crake crack cargo carack croaky creaky cracky carioca curacao curacoa carrack cark cork croc grig grog corky creek crick crock crook cruck grego