Parallel to the Unicorn AU, is a AU where Adrien never got the Black Cat Miraculous.
The Hare AU
He never properly got into school and instead got stuck at home. With tutors. And his absent father and Natalie.
Adrien has enough and with little convincing to Gorilla, Adrien runs off. But what he didn't tell Gorilla was that he was planning on escaping Paris entirely.
His plans are cut short when comes across the Guardian of the Story Book, Mother Goose aka Gospel Arwa. He is taken in by her when the police are called to find Adrien after he 'failed' to appear at a photoshoot.
From there he hides in the kind lady's home, not to aware of the danger of being y'know, a celebrity child in a stranger's house-
But he takes the new environment to explore. It's a old refurbished Library, and finding the accidental bookcase that hid the Story Book.
He meets Hopps, the Hare Kwami of Escapism.
She's aloof, she's calm, she's immediately tied to Adrien because of his needs to explore and be a real kid for once.
Gospel finds out that Adrien found out there is infact another group of magical creatures in Paris. So she helps change his identity, gives him Hopps to assist the boy adjust to normal life, and enrolls him into College Dupont to start him out.
Season 3 on, that is where the AU starts plotwise.
He meets Lila and Marinette, just in love with the latter.
Lila doesn't know who he really is, so he's safe. But Lila has a hunch.
Marinette is the school outcast for not believing Lila.
She's still Ladybug, and some girl is Chat Noir. Her alternate name is Diablo del Gato. Cowboy themed.
He decides soon on that it will be smart (not really) to assist as Hippity Hop (Hop for short) and with a long range bugle as his weapon and lucky rabbit's foot on his hip,
A new hero emerges!
TL;DR: Adrien runs away and is taken in by the Story Book Guardian. Changes his identity and enrolls in school by Season 3. Becomes Hare/Rabbit themed hero, becoming new guardian of the Story Book.