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.
grader grater gridder guarder greater grodier greedier crater cruder corder garter carder krater greeter grouter crowder gritter curdier grottier garotter groutier cruddier garroter grittier curter carter quarter critter courter curator creator corduroy corridor courtier cowriter creature criteria quartier
reader broader treader grader parader trader forrader hoarder redear crowder readier barrater ridder hardier radar boarder greater guarder greedier reedier marauder braider reorder cruder breeder rider shrewder wordier warder derider joyrider torrider larder rater broidery order prudery irater tireder corder parador narrater lowrider frater horrider herder krater brooder cruddier rudery mirador murder girder prater gridder broider toreador lardier rudder grater curdier broodier redder prodder arider raider prouder carder grodier ruddier ruder crater birder tardier rowdier border harder nerdier treater weirder shredder yarder
grad grade garda gardai grat grate great grid gride groat grody