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.
whippets wipeouts wapitis
lappets moppets poppets puppets sippets tappets tippets whippets pets peats poets nepetas pipets repeats
whipped whippet whapped whipt whopped whupped