Darker rhymes with:
barker, harker, marker, parker, polymarker, starker, barker, corker, dierker, forker, forquer, harker, kaercher, marker, millworker, new-yorker, parker, polymarker, porker, starker, yorker, zuercher
Darker sounds like:
derocher, derosier, dierker, draeger, drager, dreger, drescher, dresher, dresser, dressier, droser, drucker, dryser, durocher