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.
droop droopy drop troop dorp drip trop trope drupe drape drapey drippy troupe towrope tarp trap trip
droop troop trop rope ropy roup crop croup grope hyperope group preop prop pyrope droopy drop towrope trope
door duro rooter rootier rotor