In some stories, a person who is insane or at least eccentric may at the same time be one of the kindest and most generous characters. There may be various reasons for this: for example, such characters may preserve childlike innocence lost by the "normals", or their madness (especially if it is of religious character) may inspire them to do things that are considered "irrational" or "meaningless", like assisting a seemingly desperate cause or sacrificing oneself for the Greater Good. This trope is Older Than Print: in medieval times, it was common belief that eccentrics and weirdos were "touched by God", and many saints and blessed ones behaved in a quirky manner.
Contrast Insane Equals Violent. Not to be confused with Kindhearted Simpleton and Dumb Is Good: while these two tropes imply low intelligence, a Loon with a Heart of Gold may be smart, but quirky/unhinged.
- The Gaian Tarot, created by Joanna Powell Colbert, has such a card called the Teacher (also known as Holy Fool and Crazy Saint). According to the description, "Crazy saints speak in riddles, they tease, they laugh uproariously and act intentionally ridiculous. At the same time, they are guileless, transparent and open to a sense of wonder."
- Amélie: the eponymous heroine is a Cloudcuckoolander with strange fantasies, whose life goal is to bring people happiness (in accordance with her personality, she does it in bizarre ways).
- Ace Ventura may be a complete lunatic, but he's also a Friend to All Living Things. (Except bats, but he ends up facing that head-on.)
- Marianne Engel from The Gargoyle is a clearly unhinged sculptress of gargoyles, with her madness having religious overtones (she talks to unseen apparitions in Latin, etc.). She physically and psychologically helps the main character after a crash that leaves him severely burned and crippled.
- Emmanuel from Boris Akunin's Sister Pelagia series is a saintly mad prophet who possibly has supernatural powers and makes people whom he meets understand their flaws and change for the better.
- Lori from Thomasina, The Cat Who Thought She Was God by Paul Gallico is an apparently crazy girl who says that she sees angels and can talk to animals. She also has a gift for healing sick animals.
- Jenny Wren from Our Mutual Friend; interestingly, she seasons this with Deadpan Snarker.
- Stargirl by Jerry Spinelli: the sane, but extremely quirky titular heroine is literally the kindest and most pure-hearted character in the novel, making her classmates look like jerks in comparison (the protagonist even jokingly tells her that she's "running for saint").
- Auri from The Kingkiller Chronicle is a kooky yet good-natured girl who helps out Kvothe in various ways. It is implied in The Slow Regard of Silent Things that her quirkiness and her high moral standards are interrelated: she sees all things as sapient, and believes that even a little bit of self-interest on her part would violate the laws of the world.
- Professor Selkeem aka Axel from Molly Moon series is an unusual case, since his madness is a direct consequence of his moral qualities and self-sacrificial love. In order to protect his wife, he agreed to transport Princess Fang and her people in time, and multiple time travels shattered his mind.
- Luna Lovegood of the Harry Potter series is a Cloud Cuckoolander and a total sweetheart, if sometimes unsettlingly direct.
- Cousin Jimmy from Emily of New Moon hasn't been "all there" since a childhood accident. Emily's not sure what part of him isn't "all there," but she knows his heart is firmly in place, as he's always kind and respectful to her.
- Dagail of Oblivion certainly qualifies. The old mystic has a hereditary condition that makes it difficult for her to communicate with others to the point she was forced to retire from the Mages Council and take-up stewardship of a backwoods Guild Hall. A magic charm is all that keeps her lucid, but even without it she is a sweet, intelligent, deceptively powerful master mage. Whether you need Mysticism training or want some back-up evading demonic cultists once you enter the Guild Hall the old senile wood-elf has your back.
- Fran Bow has Fran herself: an innocent, polite little girl who suffers from vivid and often horrific hallucinations. Maybe.
- Hello Charlotte: Charlotte is easily the nicest character in the game, but she's... odd, to say the least.
- In the Shadow Hearts series Roger Bacon, appears to be a senile old man living alone in Wales. It is an act though - he is one of the smartest people on the planet but plays senile to avoid having to interact with others, finding most people to be selfish and short-sighted. Show him an even halfway decent human being though and he will go to the moon and back for them, and thats no metaphor!
- Elan the bard in The Order of the Stick is The Fool and, while not quite mad, is certainly eccentric, considering he believes his own hand puppet is a god and puts adherence to dramatic convention well before common sense. He's also unconditionally kind and loving to everyone, even offering mercy and forgiveness to his evil brother who had repeatedly tried to kill him.
- My Little Pony: Friendship Is Magic gives us Pinkie Pie, a loopy Genki Girl whose mission in life is to spread as much happiness and laughter as she can.
- The DuckTales (2017) version of Fethry Duck is this. Despite the isolation from working in Scrooge's underwater research lab taking a toll on his psyche, he is a genuinely sweet guy who is fascinated by marine life and repeatedly takes steps to keep Huey and Dewey (whom he calls "Little Donalds") out of danger.
- Gravity Falls has Mabel Pines, a quirky girl with strong, sometimes troublesome Cloudcuckoolander tendencies, as well as the tendency to inadvertently hurt people when trying to help them. She's still an All-Loving Heroine whose heart is nonetheless in the right place.