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.
cheaper cheeper shaper chipper chopper chippier choppier shipper shopper
leaper cheaper reaper heaper aper seepier keeper wrapper rapier rapper lapper peeper papery napper knapper gawper raper dapper diaper tapper weepier gaper shaper yauper leper capper soapier weeper whapper caper paper hepper beeper mapper soaper japer pepper pauper sapper napery japery apery zapper deeper taper cheeper yapper yawper per
cheap cheapie cheapo chap chape chapeau chappie cheep schappe