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.
frosh fresh fairish farouche foreshow freesia fourchee
frosh boorish noirish marshy marish qursh currish gursh resh crash roshi rush bearish boarish trash poorish whorish parish rash brush carroch moorish marsh qurush queerish crush garish caroch girsh brash harsh fresh fairish sourish perish wearish nourish cherish