What theme do The Great Gatsby, Hamlet, Death of a Salesman, and Slaughterhouse Five all have in common?

A common theme among these texts is the idea of fate and free will. Each text examines whether human beings are masters of their fates, or whether they are predestined to make the choices they do.
In The Great Gatsby, the titular character believes in the power of free will. Gatsby believes that through hard work and ambitious displays of wealth, he can overcome the stigma attached to the poverty into which he was born. Fitzgerald suggests that Gatsby was always fated to be different from the “old money” (as represented by the Buchanans). Gatsby may have exercised his free will to become rich, but he cannot escape his ultimate fate.
Similarly, Hamlet is torn over whether to murder Claudius as his father’s ghost instructs him to do. Hamlet's ability to choose how he responds to this situation would indicate that Shakespeare is saying that we do have a say in what happens. Despite this, Hamlet’s inability to choose ultimately leads to the same outcome (in terms of Claudius's death) as would have resulted if Hamlet had immediately obeyed the spirit’s request. This suggests that fate still ultimately has the power.
Willy Loman, in the other hand, seems to be in control of his destiny. Loman’s increasingly dysfunctional family life, paired with his declining professional life, contributes to Willy’s depression. Seeing no other option, Willy commits suicide so that his family can inherit a life insurance policy that he believes will solve all of their problems. While tragic, this ending suggests that people control their destinies through active participation in their lives—or even the ends of their lives.
Finally, Billy Pilgrim probably encounters the most explicit criticism of free will out of all the characters. The Tralfamadorians explain to Billy that all moments in time have already occurred, so there is no such thing as free will. Because all of time is stored in an infinitely repeating loop, only human beings think they have any choice in what happens to them. This bleak outlook echoes the idea that the trajectory of one’s life is fixed even before birth.