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.
tiff teff tuff diff toff taffy toffy dieoff taffia toffee dif doff tufa daff duff tofu tivy daffy deify tafia tophi
biff iff jiff quiff miff riff diff tiff whiff if