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.
riff rif raff reif rife ruff reify ruffe raffia ref reef rive roof reefy reive
biff iff jiff quiff miff riff diff tiff whiff if