Childe Harold's Pilgrimage, by Lord Byron, is mentioned in Arcadia. It is the first poem that earned Byron wide-spread popularity. It tells the story of a melancholic medieval man's travels around Europe.
The Seagull by Anton Chekhov (in one case translated by Tom Stoppard) is a seminal Russian play from the late 19th century that Stoppard tackled in the late 20th. It tells the story of a famous actress mother and her struggling playwright son and their guests on a country estate.
Frankenstein by Mary Shelley, published in 1818, was deeply influenced by the Romantic movement, and tackles similar themes of science versus nature.