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.
teugh tough toughy toughie teff tofu toph tufa tuff
teugh ugh waugh tough sugh sough saughy saugh roughy pugh neigh rough lough laugh kiaugh cough vugh toughy faugh weigh