The image of Prometheus runs through out early Romantic texts.  Not only does Mary Shelley link Frankenstein to the myth, but Lord Byron adapts the myth with his closet drama Manfred and Percy Shelley does the same with Prometheus Unbound.  Below are samples which tie Manfred and Prometheus Unbound to Mary Shelley's use of the myth.

Byron, Manfred (1817)

But Grief should be the Instructor of the wise;
Sorrow is Knowledge: they who know the most
Must mourn the deepest o'er the fatal truth,
The Tree of Knowledge is not that of Life.
. . . I have done men good,
And I have met with good even among men--
But this availed not: I have had my foes,
And none have baffled, many fallen before me--
But this availed not:--
(1.1.9-12, 17-21)

And then I dived,
In my lone wanderings, to the caves of death,
Searching its cause in its effect; and drew
From withered bones, and skulls, and heaped up dust,
Conclusions most forbidden. Then I passed
The nights of years in sciences, untaught
Save in the old time; and with time and toil,
And terrible ordeal, and such penance
As in itself hath power upon the air
And spirits that do compass air and earth,
. . . --and with my knowledge grew
The thirst of knowledge, and the power and joy
Of this most bright intelligence, until--
(2.2.79-96)
 

--I have gnashed
My teeth in darkness till returning morn,
Then cursed myself till sunset--I have prayed
For madness as a blessing--'tis denied me.
I have affronted death--but in the war
Of elements the waters shrunk form me,
And Fatal things passed harmless--the cold hand
Of an all-pitiless demon held me back,
Back by a single hair, which would not break.
In fantasy, imagination all
The affluence of my soul--which one day was
A Croesus in creation--I plunged deep,
But, like an ebbing wave, it dashed me back
Into the gulf of my unfathomed thought.
I plunged amidst mankind--Forgetfulness
I sought in all, save where 'tis to be found,
And that I have to learn--my sciences,
My long pursued and superhuman art,
Is mortal here; I dwell in my despair--
And live--and live forever.
(2.2.131-149)
 

Shelley, P.B., Prometheus Unbound, 1818-1819

He [Prometheus] gave man speech, and speech created thought,
Which is the measure of the Universe;
and Science struck the thrones of Earth and Heaven
Which shook, but fell not; . . .
and human hands first mimicked and then mocked
With moulded limbs more lovely than its own
The human form, till marble grew divine, . . .
He told the hidden power of herbs and springs,
And Disease drank and slept--Death grew like sleep.--
. . . . . . . . . . .
Such the alleviations of his state
Prometheus gave to man--for which he hangs Withering in destined pain--but who rains down
Evil, the immedicable plague, which while
Man looks on his creation like a god
and sees that it is glorious, drives him on,
The wreck of his own will, the scorn of Earth,
The outcast, the abandoned, the alone?--
(2.4.72-105)

To suffer woes which Hope thinks infinite;
To forgive wrongs darker than Death or Night;
To defy Power which seems Omnipotent;
To love, and bear; to hope, till Hope creates
From its own wreck the thing it contemplates;
Neither to change nor falter nor repent:
This, like thy glory, Titan! is to be
Good, great and joyous, beautiful and free;
This is alone Life, Joy, Empire and Victory.
(4.570-578)