date-fns has 140+ functions for all occasions.
jQuery WebFonts extension adds font embedding capability to jquery using the WebFonts technology. The extension provides a flexible way to choose font from a font repository and apply on html elements.
AlloyFinger is a super tiny size multi-touch gestures library for the web.
grafi.js is a library intended for learning about how image processing works. Each modules are intentionally kept small and users are encouraged to read the source code to learn about different methods and algorithms.
Prism is a lightweight, extensible syntax highlighter, built with modern web standards in mind.
CSSX doesn't inline styles so you keep your markup clean. It works directly with injected stylesheets.
Popper.js is a library used to create poppers in web applications. Common examples of poppers are tooltips and popovers.