Directors' rhymes with:
director's, collector's, collectors, collectors', connectors, defectors, detectors, director's, directors, electors, hector's, injectors, inspector's, inspectors, inspectors', lechters, objectors, projectors, protectors, reflectors, sector's, sectors, specter's, spektr's, vectors
Directors' sounds like:
detractors, director's, directories, directors, drugstores