Animate.css - Animate.css is a cross-browser library of CSS animations.
Pattern Lab - Create atomic design systems with Pattern Lab.
Animista - Create beautiful CSS animations in your browser
Storybook - Storybook is an open source tool for developing UI components in isolation for React, Vue, and Angular. It makes building stunning UIs organized and efficient.
Hover.css - A collection of CSS3 powered hover effects to be applied to links, buttons, logos, etc.
Fractal Docs - Powerful component libraries & styleguides that fit the way you work.