Settei Sets - Model Sheets
Settei sets are drawn by the Character Designer to make sure that all the moving parts in animation the in-betweeners, animators, and directors all keep the characters looking uniform, or as animators will say on model. When someone is talking about how some animation is off model this is what they are talking about; the animation does not match what the character designer intended. A note on finding these you will mostly find these in photocopy format, and occasionally the hand drawn sets will come up, these are generally rare and super expensive.