A few, named after historical people who exemplified these traits:
Ambrose. This character can read - quietly. A very rare skill in the Middle Ages. Boosts to intrigue and learning and stewardship, but a decrease in all vassals' opinion.
Jean. This character is a stickler for formal rites, ceremonies, and chivalry. Boosts to monthly prestige and piety, a slight increase to diplomacy and temple vassals' opinion, but a drop in stewardship and landed vassals' opinion. Dislikes Rufus.
Rufus. This character is the opposite of Jean. They blaspheme, burp, and break things. Decrease to monthly prestige and piety, a slight drop in diplomacy and temple vassals' opinion, but an increase in intrigue and landed vassals' opinion. Dislikes Jean.
John. This character is a snarky smart Alec who likes talking smack about their deities. Big hits to religious vassal and the Pope's (or Caliph's, or Fakir's) opinion, a slight decrease to health, and a slightly higher chance of a disabled child or demon spawn. An increase in learning and other religions' opinions. Zealous and craven people hate John.
Dub. This character is openly thought to practice sorcery in his or her spare time. It keeps the court in awe of their presence, but temple vassals mutter beneath their breath. Darkly. Boosts to learning and prestige and health, but ruins monthly piety, and decreases others' opinion (especially if they're a religious vassal or zealous).
Stephen: This character is a sucker for a weeping face or teary eye. They take chivalry to an extreme. Boosts diplomacy and stewardship, decreases martial and intrigue. Big hits to landed vassals' opinion if they're cruel, strong, or brave, but a slight increase otherwise. Increases temple vassal opinion and monthly piety.
Henry the Young: This character has daddy issues. He's more likely than most to rebel against his father, but tends to be popular with other rebellious youngsters and bastards.
Nicholaa: This character has controversial opinions about a woman's place, and the will to put those opinions into action. Temple vassals hate it, landed ones dislike it, but women and men with the same trait love it. Boosts stewardship, learning, diplomacy, and fertility.
And a few others...
Pious poverty: This character does everything extremely cheap due to their interpretation of piety. It hits their prestige hard, but greatly boosts stewardship and piety, drops decadence (if Muslim), and causes the opinion of zealous and content people to shoot up. Cynics despise them; landed vassals are irked.
Spartan: The same as 'pious poverty,' without the religious effects or prestige hit. Health and martial get a boost and the opinions of content, strong, brave, temperate, or diligent characters go up. Those of the greedy, hedonistic, or bankrupt go down, and there's a hit to vassal relations.
Harpist: This character can play the harp, a prestigious musical instrument in the medieval world. Boosts to fertility and diplomacy and prestige; hits to the opinion of anyone who dislikes luxury, or is deaf. Also slight hits to movement speed and stewardship.
Double-jointed: This character is as flexible as water, moving around effortlessly in ways that would make a normal person baulk or gaze in wonder. Big boost to fertility, martial, and intrigue, but a hit to piety and health, and a small hit to vassals' opinion.
Open-minded: This character does things outside their normal religious scope, such as observing Ramadan even though they're Christian or making sacrifices to saint's cults. It greatly improves relations between different faiths and cultures in their realm, but raises more than a few eyebrows among the clergy and their compatriots...
