Character development is key. Fanfictions explore how Ace and Luffy grow under Garp's influence. Maybe Luffy becomes more disciplined in some stories, or Ace learns to be more open - hearted, all thanks to their interactions with Garp and each other.
One popular ace luffy garp fanfiction is 'The Bonds of Family'. It delves deep into the complex relationships between Ace, Luffy, and Garp. It shows how their different personalities interact and how their family bond influences their actions.
I'm not entirely sure specifically what 'garp save ace fanfiction' is about without more context. It could potentially be a fan - made story in which Garp tries to save Ace within the context of a particular fictional universe, perhaps related to One Piece.
One popular garp fanfiction story could be about Garp's early days in the Marines, his training and the friendships he formed. Another might focus on his relationship with his family members in a different light, like how he interacted with his grandson Luffy during Luffy's childhood. There are also stories that might explore Garp's role in some of the major events in the One Piece world from a different perspective.