For "remarkable":
* Exceptional
* Extraordinary
* Notable
* Impressive
* Memorable
* Outstanding (can also be used for the second word)
For "accountable":
* Responsible
* Liable
* Answerable
* Obligated
* Amenable
For "outstanding":
* Exceptional
* Remarkable
* Impressive
* Superior
* Excellent
For "selfish":
* Egotistical
* Self-centered
* Narcissistic
* Selfish (this is a synonym, not a different word)
* Greedy
* Inconsiderate
* Self-absorbed
To give you the best suggestion, please provide more context or the sentence you're trying to write.