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.
grouper groper croupier griper cropper crupper grapery grapier gripier gripper grippier carper crapper creeper crepier crappier creepier corpora
grouper trouper dropper droopier dorper syrupier sirupier proper groper larruper crupper croupier cropper roupier ropier ropery trooper roper
group groupie croup croupe croupy grope