Core animation of layer effects/nodes
Motion graphics module in GIMP 3.x
I would suggest animation tool which would animate parameters of filters in Gimp3.x and G'MIC to distort the created image. Tool could also have an 2D particle system to create organical simulations.
Animation's tool UI and logic could have approaches:
- node based which would let user stack operations in node tree (like in Houdini VEX, Unity visual effect graph, Unreal Niagara, etc.)
Unity Visual effect graph: https://www.youtube.com/watch?v=SUZzJcBIK80
For 2d particle system I would suggest generation of particles similar to this: