The Deku x Aizawa dynamic runs on such a specific battery of tropes. A huge one is Dadzawa, obviously, but dialed up to eleven because Izuku’s own dad is absent. You get these fics where Shota slowly, reluctantly transitions from exasperated teacher to protective guardian, usually after finding Izuku injured or pushing himself too hard post-canon or in a villain attack. Another massive trope is Quirk Analysis, where Izuku’s notebooks become a shared language; Aizawa recognizes the strategic mind behind them and that becomes their intellectual bridge. Hurt/Comfort is practically mandatory—Izuku gets hurt, Aizawa is the one who finds him and patches him up, leading to soft moments that break his usual stoicism. Time Travel fix-its also pop up, where a future Izuku loops back and Aizawa is the only one who believes his wild story, forming an immediate, secret alliance.
There’s also a subgenre of Erasure-affected bonding, exploring how Izuku, whose identity is so tied to One For All, reacts to having it temporarily nullified in training, forcing a vulnerability only Aizawa sees. And you can’t ignore the Coffee Shop or Teacher’s Lounge AU, where they meet as civilians, with Izuku as a barista or a nervous new teaching assistant, and the slow recognition of each other’s true strength happens outside any hero context. It’s a pairing built on hidden softness and mutual, quiet respect for sheer stubborn perseverance.