Cg Monks Toolbox is a free toolset for Maya that includes a large selection of handy animation and rigging tools
CG Monks Toolbox
Morgan Loomis Tools
Morgan Loomis has a bunch of great animation tools and scripts for Maya on his website free to download. You can download the full animation shelf or get them individually!
Animation Buffet
Animation Buffet is a great resource for free Rigs and is constantly updated by Jean-Denis Haas (ILM)
Action VFX (FREE+)
Action VFX has a collection of free VFX that are useful for adding post effects to your animations. There is also a much larger collection available for purchase.
Josh Sobel Rigs (FREE+)
Josh Sobel has some great affordable rigs (his Kayla rig is especially great). You can also get his Bonnie rig for free!
Bancroft Brothers
The Bancroft Brothers is an animation podcast that provides an entertaining and educational look at animation. Tom Bancroft and Tony Bancroft discuss the art and business of animation with some of the industries biggest talents from Glenn Keane to Brad Bird to Don Hahn.
Animation Paper (FREE)
Animation Paper is a popular free software for hand-drawn animation created by Niels Krogh Mortensen
GDC Tricks of the Trade 2016
GDC Tricks of the Trade 2016 has some amazing tips from industry veterans. If you haven’t seen this already you need to watch it right now!
Daz 3D (FREE)
Daz 3D – A 3D morphing, posing, animation and rendering suite, normally retailing at $249 but is now free to download
Animator's Resource Kit 