Sometimes you just want to create the aesthetic of stop motion, with rough jumps between the keyframes and no tweening at all. Aardman Studio produces this in Clay or CG. One of the main features needed is to establish a cycle. That can be a sequence of legs, fishes or birds - always one model for each key, so you can easily change one key, without affecting any other keys in the cycle. Finally, it works for you with images or sketches - in short, 2D. To slow down the cycle or to stop it completely, you can use the slider solution to put the speed on zero. If you like, you have an animation with no keyframes for this section.
(The Images are for the tutorial use only, thanks)