Pencil2D is an easy, intuitive tool to make 2D hand-drawn animations. Pencil2D is open source and cross-platform.
License: GPL-2.0
Web page: http://pencil2d.org
Source code: https://github.com/pencil2d/pencil
Translate: https://www.transifex.com/pencil2d
Report the bug: https://github.com/pencil2d/pencil/issues/new