Poses.
Specifically female poses.
Poses for comic artists.
Anime artbooks.
Timed figure drawing.
Don't think about it too hard.
Animal references.
Faces, bodies, and textures.
Study Baroque shading.
Timed figure drawing.
Random pose practice.
Rotate 3D models.
Various pose references.
3D pose library.
Manipulable 3D mannequin.
Manipulable 3D mannequin.
Manipulable 3D mannequin.
Find unusual angles.
Design clothes in 3D.
3D models of the human body.