Existing objects can be imported into your scene in TiltBrush.
Google Blocks is a VR program that lets you design 3D objects in immersive Virtual Reality using only six different tools. Creations can be exported as 3D files and can be saved for 3D printing.
The zSpace programs VIVED Science and VIVED Anatomy allow you to create lessons using the dissectable 3D objects. These lessons are saved to the zSpace machine itself and then can be loaded by other users. Lessons can include labeling quizzes and reconstructing the parts of the item.
For more information, see the "authoring" videos at the links below.
Other software available on zSpace lets you work with 3D models.