Synfig Studio is an open-source 2D animation software for creating film-quality animation using vector and bitmap artworks. It eliminates the need to create animation frame-by frame, allowing you to produce 2D animation quickly. Synfig supports layers of various types such as geometric, gradients, filters, distortions, transformations, and fractal.
It has a full-featured bone system allowing to create cutout animation using bitmap images. The Skeleton Distortion layer lets you apply complex deformations to bitmap artwork.