Quadruplets as main characters? That's such a fun niche! One book that immediately comes to mind is 'The Four Twins' by Lucy Fitch Perkins. It’s an older children’s book, but it’s charming—centered around four identical sisters navigating life with distinct personalities. The way their dynamics unfold feels so authentic, like a mix of chaos and heartwarming camaraderie. It’s not just about their identical looks; their individual quirks drive the plot, from mischief to tender moments.
Another gem is 'The Penderwicks' series by Jeanne Birdsall, where the four sisters aren’t quadruplets but share that tight-knit, multifaceted sibling bond. While not genetically identical, their interactions have that same 'quad energy'—clashing and complementing each other in equal measure. If you stretch the definition, manga like 'Yotsuba&!' also capture that quadruplet vibe, though it’s more about a single child and her quirky neighbors. Still, the playful group dynamics might scratch that itch!