I was actually thinking of something similar to this topic yesterday! I wanted to draw Peregrine so I was going over her personality in my head.
How I picture Peregrine..... in a summary in case people want to guess/make their own "pictures" of her before they read mine
Peregrine's name, appearance, and the way she generally carries herself is heavily inspired by actor Peter Davison, specifically his Doctor from Doctor Who (not to be confused with Peter Capaldi). Peter's Doctor had a charming, carefree, youthful atmosphere to him, and a unique and quirky sense of style that worked oddly well. I wanted all that for Peregrine.
I picture her as the type who would balance on a stone wall or play hopscotch on the cobblestone when she's happy, or throw a ball in the air while she's thinking. If she was happy enough she could go down the street twirling and skipping with little or no fear of other people's judgments. She is quick to laugh.
But even with all that, she is also mature as she can be, observant, insightful and empathetic. She knows there's a time to be joyful and a time to be solemn. She's a passionate resister, a capable fighter and a helping hand. She wants to encourage her friends, and be there for them when they're in a rough place.
She's stylish, with a knack for color and aesthetics. She has the eye of an artist. She likes to lean towards casual but not lazy, suited up but not fancy or "ball-ready," quirky and fun but not ostentatious, and overall modest and thoughtful.
I'd like to think of her voice as matured and level but also lively and awake. Not very shrill or high-pitched, but not too deep either.
This character has a lot of "me" in it, with a healthy amount of Peter Davison and maybe a dash of Bert from Mary Poppins mixed in. Sometime soon I'd like to draw her with all these traits in mind.
As for how I see other people.... let's see.......
I see @Ariella_Newheart's character as wise, warm-hearted and kind, but also fun and playful, almost mischievous. She has the kind of voice that you could listen to all day because it's so soft and warm and happy.
@Iliara_Mustardtop's character comes across to me as an extroverted counterpart to Ariella's character. She's a dreamer and a schemer. She's a master of disguise and acting; she can drop people's guard with her sweet voice and open, caring ways. She's sweet and kind when she isn't acting too.
@Nola_Applequill's character (bless her soul) was sharp, observant, thoughtful and fierce. She had the bright and piercing eyes of an archer or a sniper. She reminded me of an eagle in many ways: precise, quick, agile, relentless, almost deadly...
I will probably continue the list sometime soon... 
