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.
wacko whacko wack wacke wacky whack whacky wick wauk weak wake wag wog wok week weka woke
wacko whacko shacko jacky jack gecko hack pack wrack tack sicko taco guaco shack back wacky shako jocko bucko wacke quack quacky whack cacao wack tacky socko rack sack knack mako mack lack cuckoo whacky yack