Holdren rhymes with:
coldren, coldren, andren, bundren, coldren, condren, fondren, hendren, mandarin, aldebaran, amparan, anaren, andren, askren, bargeron, bundren, cameron, catherine, coldren, condren, corcoran, cothren, fondren, halloran, hefferan, hefferon, hendren, holleran, holloran, killoran, lutheran, mandarin, margarine, milliron, motoren, nitroglycerin, nitroglycerine, o'hallaron, o'halloran, o'halloron, ohalloran, operan, orgeron, pickren, saccharin, saharan, tamarin, tiberon, uterine, veteran, voltaren
Holdren sounds like:
halderman, halterman, helderman, holderman, holterman