Spine - Spine is 2D animation software designed specifically for software and game development.
Animaze by FaceRig - Livestream or Video Chat with custom 2d & 3d animated avatars. Add backgrounds & props with the Animaze editor. Use on Twitch, Discord, Skype, Zoom, & more
Live2D Cubism - Live2D is the world's first drawing technology to enable 3D rendering of 2D images.
VUP - VTuber Maker & Animation & MMD/Live2D facial capture software.
Synfig Studio - Just another WordPress site
Mug Life - Create 3D characters from any photo.