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.
gridder grader guarder gritter grodier grittier grottier cruddier greedier groutier cruder grater corder garter carder greater critter curdier grouter crowder greeter corridor courtier quartier garroter criteria cowriter garotter carrotier carter crater curter krater courter creator crittur quarter
ridder gridder weirder derider lowrider raider redder rider rudder ruddier arider braider birder broider broidery horrider girder joyrider cruddier prodder torrider shredder