We have a simple example in the assimp-repo. You can find it here: Simple Snake as a FBX-File
It is just a snake with a simple skeleton with the following form:
parentbone -> childbone -> childbone -> ...
You can use it to test you bone-implementation.
The examples used in the most tutorials are containing animations for characters. The snake contains just one tree with some vertices modified by the vertex-weights stored in the aiMeshes.
When this example works try your human.