For a person who is unexpectedly insightful or clever:
* Astute: Sharp, perceptive, and having a keen understanding.
* Sagacious: Wise, discerning, and having sound judgment.
* Intuitive: Having a strong sense of knowing something without conscious reasoning.
* Unassuming: Modest and not drawing attention to oneself, but capable of surprising depth.
For a person who is unexpectedly bold or courageous:
* Understated: Quiet and restrained, but with a surprising inner strength.
* Unpretentious: Simple and humble, but capable of surprising acts of bravery.
* Reserved: Shy and withdrawn, but capable of surprising bursts of energy or action.
For a person who is unexpectedly creative or artistic:
* Quietly brilliant: Having hidden talents and a surprising capacity for creativity.
* Understated genius: A genius who doesn't boast or show off, but whose work speaks for itself.
* Unsung hero: Someone who works quietly and without fanfare, but whose contributions are deeply impactful.
Other options:
* Paradoxical: Seeming to be contradictory or surprising, yet ultimately consistent.
* Intriguing: Arousing curiosity or interest because of something unexpected or unusual.
Ultimately, the best word depends on the specific context and the specific qualities you want to highlight.