Spine - Spine is 2D animation software designed specifically for software and game development.
Unity - The multiplatform game creation tools for everyone.
Synfig Studio - Just another WordPress site
Godot Engine - Feature-packed 2D and 3D open source game engine.
Live2D Cubism - Live2D is the world's first drawing technology to enable 3D rendering of 2D images.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.