css-vars-ponyfill
Client-side support for CSS custom properties (aka "CSS variables") in legacy and modern browsers
idb-iegap
Polyfill that makes IE10 / IE11 support the full IndexedDB specification by implementing compound and multiEntry index handling
nth-grid
Nth-Grid is a versatile semantic CSS grid system with legacy browser support for Less, PostCSS, Sass, and Stylus.