Cascadeur is a unique physics-based animation software that gives animators the ability to create realistic action sequences of any complexity without the help of motion capture. Sign up for the next beta testing phase HERE
Advanced Skeleton has been used to rig creatures, props, vehicles and just about anything since 1999. It is free to download but if you want to use it for a commercial project you will have to buy a license.
The Setup Machine enables Maya users to easily and quickly rig a wide variety of CG characters with just a few clicks. Generate a flexible, modern character rig in minutes saving you days or weeks of work
Rough Animator is a fully featured hand drawn animation application that runs on Android, iOS, Mac OS, and Windows. Currently available for $4.99
Storyboarder is a free open-source piece of storyboarding software that makes it easy to visualize a story as fast you can draw stick figures.
Akeytsu is a piece of 3D animation software and is a lighter, faster and cheaper alternative to Maya. It also has a free educational version.
Krita is a free app for digital painting but also supports 2D animation. It is made by artists that want to see affordable art tools for everyone.
Live2D has a bunch of software that allows 2D artists to create animations from their artwork. Available in both FREE and PRO versions.