Grabens rhymes with:
robin's, robins, robins', robin's, robins, robins', bourbons, cabins, carbons, cubans, fitzgibbons, fluorocarbons, gibbens, hertzenleben's, hydrocarbons, mccubbins, ribbons, robin's, robins, robins', rubens, suburbans, toobin's, turbans, urban's
Grabens sounds like:
girobank, grabbing, grabinski, grapevines, gribbins, grievance, grievances, grieving, griffin's, griffing, griping, gripping, groping, grouping, groupings, gryphons