Centaurs are such fascinating creatures, and it's a shame they don't get more spotlight in literature! One that comes to mind immediately is 'The Chronicles of Narnia' series by C.S. Lewis. While not the central protagonist, centaurs like Glenstorm play significant roles—wise, noble, and deeply tied to the lore of Narnia. Their presence adds this majestic, almost mythical layer to the battles and politics of the world.
Another deep cut is 'Xenocide' from Orson Scott Card's 'Ender' series, where the planet Lusitania has centaur-like beings called 'piggies.' They’re not traditional centaurs, but their half-human, half-animal form scratches that itch. I love how Card explores their culture and biology—it’s sci-fi but with that mythological flavor. Honestly, I wish more authors would take risks with centaur characters beyond just background warriors or sidekicks.