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.
cyder ceder cider cedar citer seder sadder seeder seedier hysteria
cyder hydro leadier cheder eider muddier deer wadder odder ladder needer deader aider heder gaudier rudery louder powder adder dere hydra codder raider hider header moodier fodder nodder shudder shedder chowder wider wedder tidier dodder seeder cider ruddier shader giddier weedier lieder dowdier sadder rowdier doer readier gadder redear guider ridder dear fader beadier gaudery voider heeder powdery judder bedder bider beader padder loader ruder headier feeder bawdier seedier kneader kidder nuder udder badder mudder budder woodier leader madder needier faddier lewder lader reedier gaydar redder coder reader bidder rider lauder doddery weeder shoddier hoodier chudder rudder ceder seder deedier tedder wader widder chider shadier shuddery