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.
shedder shudder shuddery shoddier shader cheder cheddar sheeter shadier chudder cheddary chider shouter chowder cheater chuddar shooter shatter shutter shittier shoetree chadar chador chadri chatter chitter
bedder shedder wedder redder tedder lieder padder kneader mudder heeder redear leader kidder weedier muddier heder codder cheder reader giddier ridder ruddier sadder seeder deader dodder needier fodder wadder needer shudder widder header feeder madder chudder cheddar faddier adder doddery ladder eider budder bidder beader nodder odder weeder lewder badder gadder judder reedier rudder ceder seder seedier deedier udder shoddier shuddery