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.
gripier grippier griper grapier gripper groper grouper grapery crepier crappier creepier croupier carper crapper creeper cropper crupper corpora
gripier rapier chirper tripper drippier syrupier riper ripper ropier roupier crappier creepier crepier croupier grapier griper gripper grippier preppier sirupier dripper droopier trippier chirpier
grip gripe gripey grippe grippy gripy