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.
gripper grippier griper gripier groper crapper grapier grapery crupper cropper grouper crappier carper creeper crepier creepier croupier corpora
gripper dripper ripper tripper crappier trippier crupper wrapper trapper drippier rapper reappear riper frippery griper gripier grippier preppier cropper crapper dropper chirper
grippe grippy grip grappa gripe gripey gripy