Unlike Skyrim or Fallout, mods for this game are centralized in a few specific hubs. You won't usually find them on Nexus Mods.
You can find mods that introduce hairstyles from other series, such as Blue Lock (Isagi, Nagi, and Chigiri), or even Inazuma Eleven (Kido Yuuto). There are also texture mods for better eye details, "manga-accurate" uniforms, and real-life national team emblems. captain tsubasa: rise of new champions mod