Synfig Studio - Just another WordPress site
Spine - Spine is 2D animation software designed specifically for software and game development.
Animation Paper - Animation Paper is a software package for doing 2D animation.
DigiCel FlipBook - Whether you do 2D, 3D or stop motion Animation, DigiCel FlipBook makes animation easier!
AnimeEffects - AnimeEffects is a 2D keyframe animation tool based on deformation of polygon meshes.
CelAction 2D - CelAction 2D is the name of a powerful and highly advanced 2D animation program for the perfect creation of 2D animation.