Limber for After Effects is described as 'Limber is an IK system for After Effects that uses shape layers to make customizable limbs for character animation'. There are seven alternatives to Limber for After Effects for Windows, Mac, Adobe After Effects, Linux and Online / Web-based. The best alternative is Synfig Studio, which is both free and Open Source. Other great apps like Limber for After Effects are enve (Free, Open Source), DragonBones (Free), Rubber Hose 2 (Paid) and Joysticks n Sliders (Paid).
Synfig is a free and open-source, industrial-strength, vector-based 2D animation app designed for producing feature-film animations. It eliminates the need to create animations frame by frame. It is available for Windows, Linux, and macOS.
Rubber Hose is an After Effects tool for animation rigging. Connect layers from Illustrator and Photoshop into two new stretchy rigs – RubberPin and RubberRig. Style hoses unlike ever before. Major speed updates and key-frame baking let you work faster.
Joystick controllers are commonly used in 3D character rigging for facial animation. With this tool, you simply set five consecutive keyframes to represent your origin, right, left, top, and bottom extremes.
Free and open-source software for creating amazing 2D motion graphics and vector animations. Free and open-source We believe that everyone should be free to learn and create professional designs and animations, or at least to have a chance at doing it.
Duik is a comprehensive animation and rigging toolset for Adobe After Effects. It provides the main rigging tools, found in any 3D software, like IK, controllers, and bones, which you can use in any 3D software, but adapts them to 2D animation in After Effects.