Downtown rhymes with:
abbotstown, abbottstown, town, towne, uptown, abbotstown, abbottstown, brown, browne, clown, crown, crowne, down, downe, drown, facedown, frown, gown, lown, mccoun, mccown, mcgown, mcquown, noun, renown, run-down, shoun, town, towne, uptown
Downtown sounds like:
damnation, dandeneau, dantin, danton, dantoni, dantonio, dantuono, demotion, denden, denomination, dentin, dentine, dentino, dentition, denton, dentton, detention, detonation, diantonio, diminution, dimunition, domination, donathan, donation, downtime, dundon, dunedin, dunton