WordNet (r) 3.0 (2006):

rainmaker
    n 1: executive who is very successful in bringing in business to
         his company or firm
    2: American Indian medicine man who attempt to make it rain

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "rainmaker":
   Dry Ice, aeronaut, aeroplaner, aeroplanist, air pilot, airplanist,
   artificial nucleation, astronaut, aviator, barnstormer, birdman,
   captain, cloud seeder, cloud-seeding, commercial pilot, copilot,
   crop-duster, flier, instructor, jet jockey, licensed pilot, pilot,
   rain doctor, rainmaking, seeding, silver iodide, stunt flier,
   stunt man, test pilot, wingman