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.
screak screaky scrag scraggy squark scroggy
screak creak carack carrack crack crake creaky creek croak greek bookrack muckrake rickrack screaky
screw scree screwy sacra scar scare scarey scarry scary score scoria scoriae scry scurry sucre escrow