Post date: Jun 18, 2016 2:47:14 PM
The novel Black Beauty (1877) and its titular equine character are clearly in the public domain. Calling it an adventure novel would be a stretch but the character was re‐envisioned as an adventure character in derivative works that are not yet in the public domain. (Comic Vine)
The character Black Fury (May 1955) might be related to Black Beauty.
Whether or not it is based on Black Fury, the character Fury would seem to be in the public domain as the character’s first appearance (premiere episode “Joey Finds a Friend,” 15 Oct. 1955, of the eponymous series) was apparently not renewed.