free 2D animation tool

KToon

KToon is an efficient 2D animation program that was created by animators designed for use by fellow animators. However, unlike most animation programs, this is entirely offered under a GPL license so aspiring animators can make use of it for free. The animation tool is still a work in progress so bug fixes and new versions are still being developed. Nevertheless, it already works great for creating your very own 2D animation project.