Vectorify is a powerful and free Maya tool for animators that makes it easy to repath animations
Vectorify
Pickify
Pickify is a powerful selection set tool for Maya that lets you assign a hotkey to selection sets instantly and easily hide or show parts of a geometry
Twosify
Twosify is a free tool by Ehsan Bayat for Maya that allows you to convert your animation to stepped in a non-destructive way
Sticky Mod
Sticky Mod is a free deformation tool made by fRigging Awesome studio that allows you to easily move the geometry of a model. Very useful for polishing animations.
Smart Layer
Smart Layer is a script for Autodesk Maya that allows you to adjust animation using layers in a much easier and more powerful way.
IK/FK Switcher
IK/FK Switcher is a free Maya tool that allows you to build a temporary IK/FK setup on top of your original controls, while preserving animation.
Metahuman Animator
Metahuman Animator is Unreal Engine’s solution for quickly capturing facial performances using only an iPhone and PC and is available now.
Epic Pen
Epic Pen allows you to draw directly onto your screen, making it perfect for leaving drawovers, notes and visual feedback on animations
Advanced Skeleton
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.
Animator's Resource Kit 