Constants rhymes with:
constant's, constant's, constant's, assistants, constant's, contestants, decongestants, protestants, accountant's, accountants, accountants', assistants, combatants, constant's, consultant's, consultants, contestants, decongestants, disinfectants, incompetents, inhabitants, irritants, militants, mutants, noncombatants, patents, pollutants, protestants
Constants sounds like:
concatenates, constant's, constituents, constituents'