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.
loupes lopes loups lops loops lupus lupous laps lips lapis lapse leaps lipase
jupes loupes taupes coupes supes dupes ups pes veepees popes coups cowpeas koppies kewpies nappes spies copes tawpies types cups spews pups cowpies hypes pehs toupees nappies lopes pupus rupees japes yuppies yipes shoppes chippies chappies wipes whoopies whaups hopes ropes topees apes capes dopes pipes hippies rappees puppies pupas loups hoopoes peps cepes spues jaups spaes copies topes sups rapes gapes buppies pees dups peas epees pappies teepees lupus quips ripes napes poppies sipes tepees guppies opes roups tapes peso pews pies tups mopes soups upas weepies whoopees whups chapes cheapies shapes yaups yippies yups
loup loupe lop clop slope slop plop gloppy glop flop floppy elope loppy lope loopy loop sloppy