Chaosmancer
Legend
So luck can be thing that exists, and I think halfling's luck represents it well, as it just works and the player doesn't need to decide anything (technically you could decide to not reroll, I guess, but no one does this.) Lucky feat IIRC (I banned it, though not for meta reasons) is a resource that is spent, and it is pretty hard to imagine that it is the character who decides to use it.
Pretty hard for you to imagine it maybe. But I've read perhaps a dozen or so stories with characters who have luck or probability altering powers, so it is trivial for me to imagine a character who decides to use such a thing.