Direction:
* Opposite of right: Right, opposite, converse
* West: West, westerly (in some contexts)
Political:
* Liberal: Progressive, radical, socialist (depending on context)
Other:
* Remaining: Remaining, residual, unused
* Abandoned: Abandoned, discarded, forsaken
Can you provide more context about how you're using "left"? This will help me give you a more accurate synonym.