Positive:
* Numinous: Inspiring awe and reverence; suggestive of the divine.
* Notable: Worthy of attention; remarkable.
* Novel: New and original; fresh.
* Nimble: Quick and agile in movement or thought.
* Nurturing: Providing care and nourishment; supportive.
* Natural: Existing in or produced by nature; authentic.
* Noble: Having or showing moral principles and integrity.
* Necessary: Essential; required.
* Neat: Tidy and organized; well-arranged.
* Nice: Pleasant and enjoyable; agreeable.
Negative:
* Nasty: Disgusting; unpleasant.
* Neglectful: Failing to care for; ignoring.
* Noxious: Harmful or poisonous.
* Nervous: Anxious or apprehensive.
* Narrow: Limited in scope or outlook.
* Nasty: Disgusting; unpleasant.
* Nefarious: Wicked; villainous.
* Noisome: Offensive to the senses.
* Nightmarish: Frightening and disturbing.
* Nuisance: Annoying or troublesome.
Neutral:
* Neutral: Not supporting either side in a conflict; impartial.
* Numerous: Many; plentiful.
* Naked: Uncovered; bare.
* Naive: Lacking experience or wisdom; innocent.
* Near: Close in distance or time.
* New: Recently made or begun.
* Normal: Conforming to a standard or pattern.
* Notable: Worthy of attention; remarkable.
* Nice: Pleasant and enjoyable; agreeable.
* Necessary: Essential; required.
Descriptive:
* Numinous: Inspiring awe and reverence; suggestive of the divine.
* Notable: Worthy of attention; remarkable.
* Novel: New and original; fresh.
* Nimble: Quick and agile in movement or thought.
* Nocturnal: Active at night.
* Narrative: Relating to a story or account.
* Nervy: Bold and daring.
* Nifty: Clever and efficient.
This is just a starting point! There are many more "N" adjectives out there. You can find more by browsing a thesaurus, a dictionary, or even just by thinking about words that describe things you like or dislike.