I kinda agree with the above. Any brand oil that meets specs for the engine when doing an oil change, but use the same brand when topping off between oil changes. Brake fluid, use what ever is specified for top off, but if you flush the complete system, use any approved brake fluid and then use that only for top off.
Same for coolant. Almost any coolant can be used in any vehicle, some some are not compatible with each other, so if you do a complete drain, radiator and block, you can use almost any coolant. Most vehicles today with all aluminum engines cannot tolerate the old coolants that contains certain phosphates and borates, but all can use the universal long life coolants as long as you do the complete drain and refill.
Transmissions are a different story. You may be able to use certain national brands that meet the specifications of the factory ATF, but they usually cost just as much as the stuff from the dealer. I would go with the dealer supplied ATF unless for some reason you cannot get to a dealer where you live.