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.
forestay forest foresaid frusta freest frosty fairest frowsty foreside furriest firriest fieriest first frost frowst forced varsity veriest feracity ferocity fireside frisette frizette voracity verst farced frized verist verset verste
fores foresaw foresee fares feres fires force fours frees fries froes