Henry Darger's outsider epic, The Vivian Girls In The Realms of The Unreal, is available in full, for free (thanks to the Illinois Digital Archive and the Intuit Museum)
This is maybe old news but I don't think it was well publicized. For the uninitiated, Henry Darger was a janitor who grew up in an institution for "feeble minded children", but in his adult life he quietly produced a vast, sprawling epic novel, over 15,000 pages long, and many vast accompanying paintings. These works were only discovered shortly before his death, when he moved from his small apartment into a charity nursing home.
I've been interested in Darger's work for a long time but the majority of his novel has been inaccessible until relatively recently.