.blend: Blender scene or asset library. .bvh / .fbx: motion or interchange requiring compatibility checks. Textures: materials for geometry. Reference video/images: visual guidance. Resolve uses rendered media, not Blender rigs.
This website is a catalogue linking to original downloads, not a mirror of creator archives. Check each source’s license and version instructions. The first three challenges share an archive; some packages include versions for several applications.