In the late 19th century, Georges Polti theorized that “all stories are build from 36 dramatic situations”

For example

Situation 4: Vengeance taken for kin upon kin two entities, the Guilty and the Avenging Kinsmen, are put into conflict over wrongdoing to the Victim, who is allied to both

Even though it hasn’t been written for RPG, looks like something which can still be used by GM to prepare the game.