TVPaint is a proprietary, pixel-based, 2D cartoon animation drawing program. It has a .csv export format, specially to export the animaton into other applications. CSV is a plain text spreadsheet format (=comma separated values). The exported files are: png pictures in a folder and an exposure sheet in a csv file. The animation is layered, and the pictures are randomly reusable on any frames.
My add-on is an importer for this format, based on import_images_as_files. Each picture is an individual plane object. I used animated visibility and renderability to switch between the pictures. This addon could help compositing traditional cartoon animation in Blender.