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.
boudoir budder beadier bootery bawdier bider biter bettor butter badder baiter boater bidder bawdry beader bedder bitter battier bittier buttery
boudoir gaudier sautoir sudor dor