Pencil2D: Pencil2D is a free and open-source animation software that can be used to create hand-drawn animations in 2D. It is available for Windows, Mac, and Linux.

OpenToonz: OpenToonz is an open-source 2D animation software that is based on the proprietary software "Toonz", which was used in the production of several anime titles. It is available for Windows, Mac, and Linux.

Synfig Studio: Synfig Studio is a free and open-source 2D animation software that is designed to be easy to use and can be used to create both hand-drawn and cut-out animations. It is available for Windows, Mac, and Linux.

Blender: Blender is a free and open-source 3D animation and modeling software that can also be used to create 2D animations. It is available for Windows, Mac, and Linux.

Krita: Krita is an open-source digital painting and animation software that can be used to create 2D animations and illustrations. It is available for Windows, Mac, and Linux.