Synfig Studio - Just another WordPress site
OpenToonz - OpenToonz is an animation program that is a free software version of Toonz, the animation software...
Duik - Comprehensive animation and rigging toolset for Adobe After Effects
Limber for After Effects - IK system for After Effects using shape layers as limbs for character animation
Adobe Animate - Adobe Animate is a Flash, vector animation software.
Spine - Spine is 2D animation software designed specifically for software and game development.