Smart Layer is a script for Autodesk Maya that allows you to adjust animation using layers in a much easier and more powerful way.
Smart Layer
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.
AnimSelector
AnimSelector is a free and super simple Maya script that allows you to quickly setup selection groups that you can later pickup from a GUI or assign to hotkeys.
Keyframe MP
Keyframe MP is is a compact, yet powerful, media player designed to meet the needs of animators. Features include scrubbing (with audio), single frame stepping, an adjustable playback range and bookmarks. Free Trial available.
Graph Editor Redux
Graph Editor Redux is a redesign of Maya’s curve editor toolset. Not only does it reorganize the classic graph editor functions, it provides new tools that many animators have found extremely helpful in massaging animation performances.
Animator's Resource Kit 