General:
* Ease
* Solace
* Relief
* Consolation
* Contentment
* Tranquility
* Serenity
* Peace
* Rest
Physical:
* Warmth
* Softness
* Relaxation
* Luxury
Emotional:
* Support
* Empathy
* Understanding
* Acceptance
* Love
More specific:
* Alleviation (for pain or discomfort)
* Indulgence (for luxury or pleasure)
* Reassurance (for anxiety or fear)
* Encouragement (for sadness or despair)
The best synonym for "comfort" will depend on the specific situation and the type of comfort you are referring to.