There are two categories of literary devices. There are literary elements and literary techniques. Literary elements are setting, plot, conflict, structure, climax, characters, and other parts of fiction that are essential and common to all fiction. Literary techniques are symbolism, imagery, onomatopoeia, personification, allegory, allusion, and other options that an individual author chooses to construct a work of fiction. Techniques are optional choices used at the author's discretion expressly to meet the author's goal, intention, and objective.
Goethe structures Faust Part I & II as a drama (play) written in German in various kinds of verse forms including German folktale verse forms and Faustian forms that Goethe developed himself. It has two separate parts divided by more than time and substance. Goethe abandoned Romanticism as soon as he introduced it and returned to Faust sixty years after the first fragment (incomplete) version was published, writing this time from a classical approach.
One technique Goethe uses is foreshadowing. For instance line 1088 ("Heaven above me: and the waves below") foreshadows the event in Part II in which Faust flys with the heavens above and the waves below. Another technique Goethe uses is symbolism. For instance, in Act I, line 1097, Goethe uses an eagle as a symbol for Faust and his desires to transcend earthly bounds of knowing ("The eagle widely soars"). Goethe also uses classical allusion that calls up stories, ideas, concepts, and characters from classical mythology and legend as in line 1084, which alludes to the Greek sun god Phoebos: "At last the weary god sinks down to night."