In my opinion, most dive operators will ask for Open Water, Advanced Open Water, &/or Deep, Nitrox (to use the gas mixtures), Drysuit & DPV (if renting the suit or scooter).
Nitrox, If you are going to use it, you need to know the benefits, risks & limitations involved based upon the mixture used. A typical Nitrox course takes 3- 5 hrs of classroom (no dives required). Deep is a useful course to learn better how you will handle problems associated with deep diving (Narcosis & reduced NDL’s) in a more controlled manor. Many operators will require this, or Adv. Open Water for some dive sites. If you are ever planning to rent a drysuit or a DPV (scooter), most operators will require a certification to use them, because if you do not know what you are doing with them, they can get you hurt quickly. As for the others, Navigation is helpful, if you are unsure on how to properly use a compass & also how to navigate by underwater landmarks. Night/ Limited vis can be fun & increase your comfort in those situations, but not a "must". Equipment is a handy course to learn how to field repair & take better care of your equipment, especially if you aren’t mechanically inclined. Search & recovery is interesting in using search patterns to avoid wasting time looking for an object & also should include how to use a lift bag to bring heavier objects up from the bottom, safely.