Leaves of Grass (by Walt Whitman) is a very unique book of poetry, in that it was a collection that kept growing from its first version in 1855. Over the course of almost 40 years, Leaves of Grass expanded and matured from the root to become what it ended up becoming in 1892: an uncensored, unabridged collection of about 400 poems, some of which (like "Song of Myself") being epic in length.

I feel that it's important to mention this book in the context of everything happening in 19th century literature and culture in regards to queerness because Leaves of Grass is rife with sublimated yet very overt queer imagery, especially between men. Oscar Wilde was also a big fan of Walt Whitman's, and they actually met in 1882. To quote Wilde: "the kiss of Walt Whitman is still on my lips."

Source: https://lithub.com/when-wilde-met-whitman/