General:
* Valuable
* Precious
* Worthwhile
* Significant
* Important
* Essential
* High-value
* Prized
Specific to monetary value:
* Costly
* Expensive
* Pricy
* High-priced
* Invaluable
Specific to ethical or moral value:
* Ethical
* Moral
* Just
* Upright
* Principled
Other:
* Intrinsic
* Extrinsic
* Subjective
* Objective
The best adjective to use will depend on the specific context and the type of value you are trying to describe.