At present, a large part of Esperanto literature consists of existing works that have been translated into Esperanto. A few gems can be found in e-text format from Project Gutenberg . There you can find Lewis Carroll’s nonsensical children’s story “Alice in Wonderland,” except it goes by “La Aventuroj de Alicio en Mirlando.” A good number of Norwegian playwright Henrik Ibsen’s works appear on Project Gutenberg as well, including such classics as “Pupohejmo.” Even Mark Twain makes an appearance!
There are plenty of works available for free on the Internet. Additionally, there are a good number of works available for purchase. You’ll find a lot out there!