Behavior Galleries

Read my blog post on how I integrate Behavior Galleries into my workflow. 
Dropmark Website 

How to Capture Animations

7 Tips for designing awesome gifs via Invision Blog

Articles

Enhance Your User Experience with Animated Transitions via Davey Heuser
The changing face of animation & interaction design via The Next Web
The Role of Decorative Animations in Web Design via Print Magazine
The Art of UI Animations via Mark Geyer
Easing Functions via Lucas Barbosa
Motion UI Design Principles via Beyond Kinetic
Transitional Interfaces via Pasquale D’Silva
CSS Animation Trends in Web Design via Envato Market

General Inspiration

capptivate.co
useyourinterface.com
ui-drops.tumblr.com
UI animation search via Dribble
GifUX via Instagram
hoverstat.es
http://uxarchive.com/animated

Material Design Specific

material design
materialup.com

Tools

mixeek.com
tumult.com/hype
www.hippostudios.co
sencha.com/products/space
bly.sk
createjs.com/EaselJS
www.sencha.com/products/space

Examples and Code Snippets

General
wow.js
animate.css
unheap.com
codepen.io

Page Transitions, Grids and Overlays
Page Loading Effects via Tympanus 
Overlay Styles via Tympanus 
Grid Layout via Tympanus 

Elements and Objects
Magic Animations via minamente 
Animations via Justin Aguilar
Element Transitions via Dan Silver 

Buttons
Circular Progress Buttons via Tympanus 
Progress Buttons via Tympanus 
Creative Buttons via Tympanus 

Navigation & Hover Links 
Link Effects via Tympanus 

Loaders
Loaders.css via Conner Atherton 
SVG Loaders via Sam Herbert
Material Design Preloader via Aaron Lumsden 
Loaders via Aaron Manoz