Bathroom wood finishing  

Virtually
any finish you would use on any other interior or exterior wood surface.
All finishes for wood are designed to deal with surface moisture and soil; no finish is capable of completely excluding ambient humidity or immersion from affecting the wood beneath the finish; all wood is subject to changes in dimension as it is exposed to moisture. So, what you want to do is keep wood dry, to the extent possible. Wiping water off of finished wood promptly, and keeping it free of accumulation of dirt and dust, is the best way to preserve it.
Lacquer, polyurethane, oil, wax. . .any of these can be an appropriate moist-environment wood finish. The first two require only the maintenance mentioned; the latter two will need periodic renewal. Wax can water-spot but can be repaired with application of mineral spirit (paint thinner) and/or more wax.

That is very helpful. Thank...
That is very helpful. Thank you very much for your time and info.
Best,
Max