I’ve come across several authors who excel in this niche. One standout is Rudyard Kipling, whose 'Just So Stories' are a treasure trove of whimsical tales that have entered the public domain. These stories are perfect for retelling and adaptation, making them a favorite among educators and storytellers. Another notable mention is the works of Hans Christian Andersen, whose fairy tales like 'The Little Mermaid' and 'The Ugly Duckling' are timeless and widely used in various media.
For those seeking more contemporary options, the stories of Arthur Conan Doyle, particularly the Sherlock Holmes series, are now largely free to use. Their intricate plots and memorable characters make them ideal for creative reinterpretations. Similarly, the works of H.P. Lovecraft, despite their controversial aspects, are often adapted due to their public domain status. These authors provide a rich foundation for anyone looking to explore or build upon free use stories.