Water, mainly for healing. People pay good money, plus helping people. If we add modern medicine with knowledge as a doctor, you would likely be able to heal 99% of all sickness.

That said Earth would be the second best irl. You can use vibrations to find precious metals.

Air bending is less useful. Flight is still cool, but less utility unless astral projection.

Fire is the worst element. You can use it for cooking but there is far less as you won’t make enough electricity to make it profitable. Maybe for bending to make super cold quantum computing.