General:
* Satisfying
* Gratifying
* Rewarding
* Meaningful
* Significant
* Worthwhile
* Ample
* Complete
* Abundant
More specific:
* In terms of work: Rewarding, stimulating, engaging, purposeful, challenging
* In terms of relationships: Nurturing, loving, supportive, intimate,
* In terms of personal growth: Transformative, enlightening, enriching, empowering
The best synonym to use will depend on the specific context of the sentence.