emotion : emotion is a high performance, lightweight css-in-js library that supports both string and object based styles.
enquire.js : A lightweight, pure JavaScript library for responding to CSS media queries.
Flume : A React-powered node editor and runtime engine. Build apps that are resilient to changing requirements by modeling your business logic as a JSON graph...
Codassium : A better way to conduct remote interviews
WebRTC based video chat + code editor = Awesome interviews
RegPack : RegPack is a packer intended for use on minified Javascript code.
It is mostly suited to small size constraints (1kb, up to 4kb).