My professor is big on finding quotes throughout this story that back up the main themes of English Literature. The themes he has us studying are Revolution, Individualism, Poetics, Nature, and Orientalism. Quotes from each volume of the novel as an example of each of these themes would be very beneficial.
So from this list of themes you gave, perhaps individualism/ identity and nature might fit in.
"Cursed, cursed creator! Why did I live? Why, in that instant, did I not extinguish the spark of existence which you had so wantonly bestowed? I know not; despair had not yet taken possession of me; my feelings were those of rage and revenge. I could with pleasure have destroyed the cottage and its inhabitants and have glutted myself with their shrieks and misery." (ch.16)
Here the monster questions who he is. The creature questions why a benevolent God would allow his creation.
"When I looked around I saw and heard of none like me. Was I, the, a monster, a blot upon the earth from which all men fled and whom all men disowned?' (Ch 10)
Again the creature asks who h is and what is his purpose on earth to live in such misery and isolation.
"The moon gazed on my midnight labours, while, with unrelaxed and breathless eagerness, I pursued nature to her hiding-places."
Here the creature longs to find solace in the natural world.
