In the essay The Soul of Man Under Socialism (1891)Wilde advocates a type of socialism in which individualism is free to thrive, which one source terms libertarian socialism.
De Profundis is a letter Wilde wrote while in prison to his lover, Sir Arthur Douglas. It is a poignant reflection of the events of his life since the two first met.
Wilde paints the picture of an inmate he encountered during his imprisonment in The Ballad of Reading Gaol (1897). This poem paints the inmate as a man no different than those outside the prison's walls.
All quotes from the above works by Wilde come from De Profundis and Other Writings, edited by Hesketh Pearson.