This is a handy website for anyone studying the 19th century (not just the Victorian Period, which is only from 1837-1901). This is the link to the John Keats portion of the site, which has a biography and timeline of his short life, as well as other great resources.
The British Library in London is one of the largest, most important collections in the world. Even if you can't visit in person, their website provides some useful information about the writers whose manuscripts are kept there. This is a link to a British Library page about John Keats.
In this video, actors act out the poem.
A music video of "La Belle Dame Sans Merci" by the Ray Archer Trio.
This is a video of a rendition of Keats's poem set to music by the group Penda's Fen.
One of the paintings by John William Waterhouse inspired by Keats's poem.
This is a link to the painting of "La Belle Dame Sans Merci" by Sir Frank Dicksee.
This image is from a magazine called Punch in 1920 – the picture is titled, "La Belle Dame Sans Merci."
This simple sketch of the poet is housed at the British Library in London.
This miniature portrait of John Keats is by Joseph Severn, and is housed at the Keats-Shelley Museum.
This is a modern photograph of Keats's grave in the Protestant cemetery in Rome, Italy.
Charles Brown was one of John Keats's closest friends, and he wrote an early biography of Keats. (It was completed twenty years after Keats's death.) This website describes the biography and has some excerpts, or you can check a copy out of your local library for the whole thing.
This is a link to the complete text of Sidney Colvin's 1917 biography of John Keats.
This is an edited collection of John Keats's letters, so if the excerpts aren't enough for you, you can check this book out of your library.