There are many more animation applications out there, not the least of which is Blender for 3D animation and all manner of hybrids (check out how some users are abusing the Grease Pencil tool for animation or the excellent Freestyle effect), GIMP Animation Plugin GAP, Tupi, the recently open-sourced OpenToonz, and many more.
In the past two months, I've covered Krita Animation for hand-drawn digital cel animation and StopGo for stop motion animation. Animation is a robust field with a large number of specialties and an even larger number of tools for creating a particular look or style.