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 "normal" people, or their madness (especially if it is of a 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 a common belief that eccentrics and weirdos were "touched by God", and many saints and blessed ones behaved in a quirky manner.
The character could be freaky or do nonsensical things, but that doesn't mean they are harmful to society, or evil in nature and morality. They are pleasant and do kind acts here and there despite what their otherness or freakiness may suggest.
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 or 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."
- Child of the Storm has Luna Lovegood, as per canon, who remains as strange and kindhearted as canon, even after becoming the second Delirium of the Endless.
- Hetalia: Axis Powers fanfic Gankona, Unnachgiebig, Unità: Between loving to tackle-hug his closest friends and his strange mannerisms, Italy sure is an eccentric one. He also happens to be one of, if the the, kindest character in the whole series.
- 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.)
- Yang Lin, the secondary character from The Condemned (1976). He speaks like a hyperactive child and Deadpan Snarker who spends much of the movie behaving like The Gadfly to his cellmate, Feng Da-gang, but when they managed to escape prison, Yang had taken a liking to Feng and decide to help him clear his name after being framed for murder.
- The 1966 French anti-war film The King Of Hearts (Le roi de couer) has a whole asylum full of these types, who take over a town that the Germans (the setting is World War One) has booby-trapped (the locals fled without bothering to evacuate them). A Scottish soldier of the Signal Corps comes to find and defuse the bomb, not knowing they aren't regular townsfolk. Bittersweet hilarity ensues.
- The Mask: The Mask unlike his unmasked alter ego Stanley is very much a cartoonish wild man but he does have a good heart and cares very much about Tina which he ends falling in love with like Stanley did and when he meets Tina in the park despite being somewhat sleazy towards to her at first he shows himself to be a sweet, kind and polite man who gives Tina a heart with an arrow through it to show her that he loves her and later at the Coco Bongo he saves her and everyone else there by eating the bomb showing himself to be a brave man who will do anything to save the ones he cares about and even to save the ones who he does not know about or does not like.
- 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 Loony 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!
- A3 has Homare Arisugawa, a noisy, Insufferable Genius eccentric poet who randomly recites poems whenever he feels like it (even in his sleep) and has a strange way of thinking and the tendency to be Innocently Insensitive. Despite that, he always means well and tries to help others. He even gladly takes care of Hisoka, even though he is fully aware of how selfish and unfriendly the Sleepy Head can be, much to Guy's confusion.
- Half-Life 2: Father Grigori is clearly more than a bit unhinged, but at the same time, all his actions toward you in-game are very much intentionally helpful, from giving you hints, to tossing you a shotgun to help fight the zombies, to enabling your escape from Ravenholm.
- Plants vs. Zombies has Crazy Dave, an eccentric loon who repeatedly mentions that he's CRAAAAZY, but he helps the player fight the zombies by giving them tips as well as selling them plants and items. It's quite telling that the minigame music played on the level he introduces himself in is called "Loonboon".
- 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.
- Len from Ennui GO! is a chalky-skinned Cloudcuckoolander Conspiracy Theorist who often dabbles in strange magical rituals, encounters Eldritch Abominations on the regular and generally freaks her friends out with her wacky mannerisms and insane ramblings. That said, she is good-hearted, believes that, while nothing in the universe truly matters, that doesn't mean you can't make your own life special and is the friendliest of the main cast.
- DC Super Hero Girls: This version of Harley Quinn is a good-natured prankster rather than a lovesick psycho. She still seems a bit crazy, but still a nice person and never (intentionally) hurts anyone with her pranks
- 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.
- The Tick. Make no mistake, the guy is a certified lunatic, Manchild, and Idiot Hero to the ninth degree. But he's a genuine hero who looks out for the city's safety and cares about the people around him, no matter how oddball his behavior may be.
- The Mask: The Mask is a wacky, genuinely insane madman and a troll as well but he is a genuine hero and very much cares about the people who live with him in Edge City and his friends like Milo and Peggy.
- Eve is a wacky, genuinely insane, man-hungry woman who also has a southern American accent and acts like one as well but she is a sweet, kind, polite and nice woman who despite being man-hungry treats Stanley very well even though she tried to kiss him lots of times and is in love with him and very much cares about him as well.
- Lady Gaga. Despite her very odd personality, she's usually really sweet. In one of her interviews, she said, "I was always a weird girl who came to school with lots of red lipstick on or my hair perfectly curled or whatever I was doing to get attention."