Animals:
* Mouse: implies timidity and a desire to avoid attention.
* Deer in headlights: suggests startledness and frozenness in the face of something unexpected.
* Fawn: emphasizes youthfulness and innocence in shyness.
* Kitten: conveys a sense of playful and innocent shyness.
* Hare: highlights a tendency to flee from attention or confrontation.
* Turtle: evokes slowness and reluctance to engage.
Other:
* Violet: implies a quiet and unassuming nature.
* Whisper: emphasizes soft-spokenness and a reluctance to be heard.
* Ghost: suggests a feeling of being unseen or unnoticed.
* Shadow: conveys a sense of being withdrawn and hidden.
Examples:
* She was as shy as a mouse in a crowded room.
* He stood there as shy as a deer in headlights when she asked him to dance.
* The little girl was as shy as a kitten around strangers.
The best word will depend on the specific context and the type of shyness you want to describe.