Abstractor, Accountant, Actor, Adjudicator, Adjuster, Administrator, Agent, Appraiser, Apprentice,Arranger, Assembler, Attendant, Auditor, Babysitter, Bagger, Breeder, Brewer, Builder, Bundler, Captain, Checker, Chief, Classifier, Clerk, Collector, Comptroller, Controller, Coordinator, Dealer, Director, Distributor, Drainer, Estimator, Eviscerator, Executive, Expediter, Finisher, Gatekeeper, Gatherer, General, Generator, Guide, Handler, Helper, Host, Hostess, Inducer, Inspector, Installer, Jockey, Judge, Juggler, Keeper, Laborer, Librarian, Lieutenant, Manager, Mechanic, Mediator, Modeler, Observer, Operator, Pilot, Planner, Polisher, Porter, Preparer, Processor, Purifier, Receiver, Referee, Repairer, Representative, Salvager, Scribe, Secretary, Sergeant, Shepherd, Stacker, Supervisor, Tender, Tester, Umpire, Winder,
Worker, Wrangler.
Much thanks goes to the Job Genie. Of course, you know, after wasting a bunch of time compiling this list I'm still inclined to stick with Manager. It just seems less contrived.
Updated on 9/15: Added Umpire, Referee and Controller
Second update on 9/15: From Ned, Judge, Adjudicator, Comptroller,
Scribe
Third update on 9/20: From Ned, Juggler