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.
repair repro reappear reaper repour raper riper roper rapier rapper ripper ropery ropier roupier wrapper
repair pair par dopier tippier zappier diapir speir spire soupier spare cuppier pipier soapier copier chippier sappier ropier rapier coappear pappier reappear nappier loppier lippier goopier gappier weepier hippier hoppier appear parr quippier peppier pare loopier seepier roupier happier nippier mopier para pear pier soppier spar spear spier spiry zippier dippier tapir typier whippier choppier
repay rep reap repo repp arepa crepe crepey crepy prep prepay preppie preppy