BodyParts3D has whole atlases of the human body that are CC-By-SA, but they were all in a web interface that wasn't very usable. In this file, I've assembled them all into Blender, fixed their scales and organization (1.6 ish meters as measured by a Default Cube or Rigify template), and organized them into collections by body system.
Things this does NOT have: materials, textures, names, female anatomy, rigging, or any other goodies. But I think if you look them up on BodyParts3D by the object name, you can cross-reference the item. There are some missing chunks of data, such as the nerves. However, it's still a great starting point. It is also limited by my knowledge of anatomy, so there might be an occasional gland floating in the digestive collection.
Special thanks to BodyParts3D for providing this data! https://lifesciencedb.jp/bp3d/?lng=en
Also thanks to Mephist0 on Blender Artists for the Import Multiple Objects script. Without it, I would have given up a long time ago. https://blenderartists.org/t/import-multiple-obj-files-for-blender-2-8x/1164372