:- same FL
:- FL grows up to be independent, trying to ensure their survival instead of relying on others. FL is witty, smart and sharp in both the dramas.
:- In both dramas, FL has a difficult childhood. (lived without parents)
:- Revenge plot for ML (family exterminated due to plotting)
:- Misunderstandings between ML and FL leading to angst
However, in The Story of Pearl Girl, the FL is determined to live independently and make her own way into business world while in Love Like the Galaxy, there is no such plotline.

But the FL in both dramas have some sort of similar outlook towards life.
(Note: Love Like the Galaxy has 2nd part too)