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Unity 2D - Unity 2D is a powerful and feature-rich game design solution built from the ground up to fulfill every basic and advanced need of the developer.
Live2D Cubism - Live2D is the world's first drawing technology to enable 3D rendering of 2D images.
Adobe Animate (formerly Flash Professional) - An animation tool that used key frame animation for games and movies.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Anima2D - Documentation Anima2D is a 2D Skeletal Animation plugin for use with Unity 5.